Hey folks! There are other things I should be writing but I couldn't get this idea out of my head. Beware: it's angstier than it sounds from the summary.

A trail of bark and debris was an annoying thing to find in one's spaceship, but when Peter stopped to question where it could have come from, his annoyance stopped cold and fear set in, even before he heard a tiny moan coming from up ahead. He followed the trail at a run until it ended in a storage room, where Rocket was sitting on a low shelf with a tree creature that looked just like Groot, but nearly twice his size.

Rocket shot Peter a look that could have meant anything, but his voice was far gentler than usual, with an evanescent note of sadness. "It's all good," he said. "Little growth spurt."

"I am Groot." He was still picking at the top layer of his wooden skin, throwing bits down at the ground in angry movements. His voice sounded frustrated, too, although it was slightly deeper than it had been.

"Wow," said Peter. The shelf didn't have head room for him to sit with them, so he crouched in front of it instead. "I was worried when I saw all that flaky stuff you were leaving behind. You're looking good though, buddy."

Groot pouted. Rocket was grooming him with a fine blade and a file, whittling away the loose bark that Groot couldn't reach. "He's upset," he clarified as a small pile of sawdust formed beneath them. "He can't ride on my shoulder anymore. Can't fit in all the places he used to. Don't think he was ready for this."

Peter considered that. "Well, you're still small enough for my shoulder." He tapped it to invite him there, but Groot shook his head and kept fussing with his bark. "Come on, growing up isn't so bad. This is like...it's like your birthday! How about that?"

That got him a blank stare from both Groot and Rocket. Groot went back to his scratching after a few seconds, but Rocket's gaze lasted longer.

Embarrassed, Peter cleared his throat. "I'm guessing birthdays weren't really part of growing up for you either."

"Can't say they were," said Rocket. For a moment he closed his eyes, though, so he must have been remembering something.

Knowing that time would be limited each night, he had taught himself a series of steps and made them routine so he could move as quickly as possible. First the cage door: easier every time, but his left foreleg was hurting badly tonight, and it was hard to use it once he was ready to scale down to the floor. He wasn't sure exactly what they had done to it, but it felt the same way as his left hind had felt not long ago, so at least they were doing it to one limb at a time. Two at once would have kept him in his cage all night.

Next he climbed up to the counter on the opposite side of the room and powered up the file reader there. It was backlit with a faint glow, which might be visible from the other side of the door if someone out there was to look for it, but even his keen night vision didn't make it easy to read in complete darkness, so he kept it on.

He had done this enough times to know exactly how to search for information on himself. All it took was his code, 89P13, and a password that the authorized users hadn't guarded very carefully. Sooner or later they would probably change it, which was just one more reason he had to work fast and study as much as possible before his access was taken away.

Words filled the screen. He had learned to read the first time they had shown him an alphabet, but as far as they knew, he was still learning. It wasn't difficult to make them believe that he was struggling with each letter, or that he had no personal interest in it aside from the usual carrot-and-stick motivators. The ruse wouldn't last forever, but every written word that he understood without them knowing about it was valuable.

He found the most recent report first. Some of the shorthand they used was still beyond him, but he worked out that it was about his left arm, and that his bones had been strengthened with a coating of...metal? Some kind of unbreakable substance, anyway. He flexed the arm, wincing, but couldn't find any outward sign of the change.

The previous report showed the same information, except it was for his hind leg. Continuing back in time through the study, he found descriptions of various operations which had been performed on his body, some of which he could associate with his memories, some which were a complete mystery. What he wanted, though, was some clear explanation of what had been done to his mind. He knew he shouldn't be able to think like he did. He shouldn't be able to read, let alone assemble a functional rocket torpedo from spare parts, which he hadn't done yet, but he was fairly sure he could.

There were no clear answers here. He found references to multiple brain surgeries, but not the secret to whatever had made them work so well, or even whether his present capabilities were actually the intended goal.

His frustration increased as he reached the end of the reports. The first one logged was a list of codes assigned to himself and other subjects born at the same time. Nothing else was shown about his littermates, and for a moment he considered looking for their files to see what had become of them. Then he noticed something else: the date on the record of the birth matched the one shown for today, albeit one year back. Did that mean something?

The sound of movement from somewhere in the compound reached his ears, and he hastily reset the program and returned the screen to the exact position where he had found it. He moved silently back to his cage, resisting the urge to run and risk making enough of a noise for someone to come and investigate.

As he settled back into his bedding, engulfed in darkness, he thought again about the dates in the report. It must have been a coincidence that today was the anniversary of his whelping. It didn't mean anything.

It looked like Groot wanted to be alone with Rocket for now, so Peter left the room, but he knew Gamora would want to know about the change right away. He found her in the mess, sitting at the table peeling something with a small knife, but Nebula was there too. It would be awkward to talk in front of her. It would also be awkward to leave instead of talking.

For that matter, it had probably already been awkward before he came in, so he sat down next to Gamora and said, "I'm not interrupting your dirty look competition, am I? Groot's growing. He's like...this big. But don't go see for yourself yet, he's bummed out right now. Did you ever have a birthday party or anything? I need some ideas."

Both women looked at him as if he were an Orloni which had somehow found its way onto the ship and learned to speak. Gamora, who at least had the advantage of being used to Peter, let a smile ghost across her face.

"Yes," she said. "But..."

For over a year, she had been so fixated on how many days she had been trapped here that she lost track of her own age. When she realized that she must have had a birthday, she did the math to figure out how long ago it had been and found she had another coming up soon. Of course it would have been easy to forget about it last year - she had only been adopted by Thanos three weeks ago. She'd had other things on her mind.

But this time she woke up conscious of it. She didn't want to be. Keeping quiet about it made her feel the loss of her world even more deeply than usual. Mentioning it to anyone would have been much, much worse. Even one of her sister-captives would react with suspicion: nobody asked for attention, or kindness, or mercy in this place. If you wanted something, you had to get it yourself, or go without.

At her first training session of the day, she remembered the annual celebratory song of her people, and it gave her a burst of anger that caused her to succeed at breaking some of her opponent's bones. The screams that followed didn't bother her. She wasn't going to hear the song, the one she should have heard every year, the one that you didn't have to earn except by being alive and loved. She had to earn everything now, and she had earned this victory.

If a Daughter of Thanos wanted something, she took it.

There were round brown rolls at dinner. Gamora watched the basket being passed down the line as everyone took one roll to have with their soup. When it reached her, she took two.

Instantly, all eyes were on her. "What are you doing?" asked Chalu, a thin orange-skinned girl.

Gamora stuffed one piece into her mouth and stared at Chalu over it as she chewed, not bothering to answer.

"If you take two, someone else won't get one." That was Nebula, quiet and logical on the other side of the table.

"It's my birthday," said Gamora after she had swallowed. "I'm having both of these."

There was angry muttering all the way down the table now. "Who cares about your birthday?" Chalu snarled. "We're all hungry. You can't take our food just because you feel like it."

"Then come get it." Somehow she had managed to finish off the first hunk of bread while arguing the point, but she kept the other in her hand, ready to defend it. "Coward," she added, noticing Chalu's hesitation.

The fight was over in seconds, it seemed. Maybe it couldn't properly be called a fight, but in any case, Chalu was on the floor, hands cupped around her broken nose. Nobody else was coming after Gamora's bread, which probably didn't look so appealing anymore now that it had been crushed in her fist, anyway.

She sat back down at her place, nibbling at her prize. Nebula was still staring at her from across the table, hand clenched around her spoon, which wasn't moving from her bowl.

"What?" Gamora finally asked.

There was a strange new quality of sarcasm and bitterness in Nebula's voice when she responded: "Happy birthday."

Gamora shook her head, unable to voice the memory that had just played out in her mind. Peter was already standing back up. "Yeah," he said as if he were responding to something in spite of her silence. "I'm probably gonna get the same thing from everyone, but I thought I'd at least give it a try. Blue? You want to do a wistful-eyes flashback of your own, or are you just gonna piggyback on hers?"

Nebula tensed, which still took Gamora by surprise every time, because she always looked like she was at maximum tension already and then she somehow took it a step further. Peter tossed his hands up as he stepped back, then dropped them again, saying, "Got it. I'll let you know if there's gonna be cake."

It was even harder to speak when he had left the mess, but Gamora was determined to never again leave room for another misunderstanding between herself and Nebula, so she cleared her throat and said what she had to say. "Peter talking about birthdays reminded me of something that happened when we were young. I took extra food and broke Chalu's nose. I hadn't thought about that in years, but maybe you never forgot it."

Nebula stared off in the direction that Peter had gone. "Your friend is stupid if he thinks the tree cares about having a party."

"What?" Gamora put down her utensil and leaned back from the table with a sigh. "You can call them Peter and Groot, you know. I don't know why you keep referring to everyone like that when you know all their names."

"They're your friends. Not mine." Nebula rose abruptly from her seat, and Gamora tried to conceal her regret at another botched attempt at healing old wounds.

Nebula turned to stalk away toward one of the corridors that led deep into the parts of the Quadrant that the Guardians hadn't yet thoroughly explored. At the hatch, she paused and turned back, but all she said was, "I wasn't thinking about your birthday."

It must have been some kind of joke to tell her she could only fight Gamora again once she was older. It must have been to shame her, to make her appear as a child to her sisters. He had promised that if she won this battle, he would reverse the last modification to her body, and then he had forbidden her to fight the battle.

But the day had come and now they were in the arena. Nebula attacked as she never had before. She was no child. She was a Daughter of Thanos. She could win this.

She lasted a full five minutes longer than she had in any previous battle, which didn't matter. In the end, she was on her knees, struggling to rise, and Gamora was kicking her weapon away from her like she always did. Sighing, like she always did. "You have to keep your guard up! I keep telling you. Both sides. You could have had it that time."

There was laughter from outside the arena, slow and subtle, but coming from more than one source. Nebula couldn't look up to find out who it was. It would do no good to challenge someone for laughing at her; they had seen her fail already and no victory would take that back.

Gamora was reaching out a hand to help her to her feet. Angrily she swatted it away and heaved herself up without aid, ignoring the pain. Worse would be coming. Thanos would take another part of her. Maybe this time it would be her heart. Please let it be my heart, she prayed as she limped away from her sister, breath coming out in a hiss.

"Will Gamora and Nebula be okay?" asked Mantis, eyes wide with genuine concern.

"Are they ever?" Peter answered. It was probably the wrong thing to say, especially around Mantis and Drax, so he kept talking before they could take it as a real question. "Gamora can handle anything. She'll keep an eye on Nebula. And it's not like I lobbed a grenade in there with them. I just asked them about their birthdays."

Drax frowned. "Why?"

"I want to do something for Groot. He's getting bigger and he seems like he didn't really want to change, and I just…" Peter shrugged helplessly. "You know how hard it can be to grow up. Maybe it would make him feel better if we paid him some special attention, but apparently nobody around here gets the concept of a birthday party."

Mantis made a sudden squeak of excitement, her fingers flying up to her face. "I do! Birthday parties are for fun and happiness! We must have one for little Groot!"

Peter sat down on the step beside Drax, watching Mantis with a confused smile. "Didn't see that coming. How did you celebrate birthdays if you spent your whole life on Ego?"

Her smile flickered.

The celestial orbit did not apply to Celestials; Ego made his own light and energy, and thus had no need for a sun. Mantis learned to calculate the passage of time based on his regular rotations, but there was little need for a calendar here anyway. Nothing ever changed on Ego.

One day he informed her that she had been living on him for the equivalent of a year on her planet of origin, and that in commemoration, she could have whatever she wanted. She didn't know what to ask for, so he gave her endless media from all over the galaxy and instructed her to use it to learn more about how people lived.

Mantis loved movies. She loved books. She preferred fiction, because it described the emotions of all of kinds of characters, and she could pretend they were her friends. Nothing could take them away from her, either. Even if they died at the end of the story, she could go back to the beginning and they would be there again, faithfully. In the real world her friends never came back after they died. Their bones had only one story, and it was too sad for her to stay near them for long.

Her next birthday brought her into her nymph state. Ego asked again what she wanted, now that knew something of the galaxy's different cultures and how they recognized the passage of time. She was prepared. Fiction had shown her so much, and she wanted all of it. She wanted company. She wanted a real life, full of love.

Fortunately, fiction had also taught her to lie. "I would like decorations and food that is sweet but unhealthy and some music."

The party was arranged almost instantly, inside a castle ballroom. Ego didn't stay, which was expected, but still a relief. He did, however, create the illusion of guests, and they laughed and cheered and sang her a song as she ate her cake. They couldn't converse with her, and she didn't have a way to turn them off, so eventually she left the castle by herself to seek quiet.

Mantis blushed. It was kind of Star-Lord to take any interest at all in her past, but she didn't want to bore him, and her ignorance would embarrass her if she put it on display. "I only know what I have read," she said shortly. "But I will help you celebrate according to the customs of your people that you think are best."

"Customs of my people don't count for jack," Peter replied, restlessly twiddling his Zune in his fingers. "What we need is some intel on the customs of dancing trees."

He was gone after spending just a few minutes with them. Mantis wished that she had been able to give him the intel that she wanted, and she said as much to Drax.

"Peter Quill does not like to sit and listen," he observed. "If he had asked me I would have helped him correct his misconceptions about the meaning of a birthday. You seem to have the same ones."

Mantis did like to sit and listen. Drax's stories weren't fiction, but in a way they were better, because she didn't have to pretend that he was her friend.

Every year, the family would celebrate Drax's birthday in the same way. First his mother would tell the story of her labor, then they would cook her favorite foods, refusing to let her do any work throughout the entire day. She was always pleased with the gifts that Drax found for her: imported fabrics, decorated pottery, sophisticated weapons.

He enjoyed celebrating his conception day, too, putting his father at the center of the festivities. Certainly he looked forward to having children of his own so that it would be his own turn to be honored for his role in giving them life. But his birthday was special, as his mother's regal pride in his birth and upbringing was special, and when Kamaria turned one year old, Drax could not have been more eager to bring the traditions to a new generation.

Kamaria, of course, couldn't celebrate her own birthday. She was a baby. Some families never acknowledged a birthday until the child was old enough to independently make a gift for his or her mother, but Drax didn't want to wait that long. Hovet deserved the best, and anyway, she had bought him an excellent pair of knives on Kamaria's conception day.

After he left home in pursuit of Ronan, he remembered his daughter's birthday every year, but Hovet was gone along with her so there was no way to mark the occasion. He remembered his own birthday, too, with great regret. His mother was still alive, back on his home planet, and with no son there to honor her.

Peter had come full circle; after talking to everyone on the ship and getting nowhere with his birthday party idea, now he was sitting with Rocket again while Groot amused himself underfoot. Rocket had made him a toy, some spinning flying thing with blinking lights, which Peter wished he had thought of first. He couldn't have made it himself, of course, but he could have asked Rocket to wrap it up in paper and present it to Groot as a gift.

"He's fine." Rocket said it like a retort, pointing at Groot with both hands to emphasize it, although Peter hadn't said anything.

"I know that." Apparently they were arguing about something, so he couldn't help it if he sounded defensive. Groot was chasing the toy, laughing, as it sped along just over his head. It was clear he was fine.

Rocket shook his head in exasperation. "So what's eatin' you? Don't make a thing about it, just say why you're mopin' around and then get over it real quick so we can quit talkin' about our feelings."

Peter felt a smile coming on, but curbed it. Rocket's aversion to speaking openly about his concern for his teammates was as real as the concern itself, and teasing him about it wouldn't do either of them any good. "Groot's gonna be our steamroller when he gets big again. I want him to remember we took care of him when he was little."

"Like I said," Rocket griped, "he's fine. Why's it all gotta be about this birthday crap?"

"It's just…" He exhaled, shaking his head. "It's just something you do for a kid, makes 'em feel loved."

"BOY! Where you hidin'?"

Peter groaned and stuffed the bot catalog under his bed. Yondu wouldn't take it away from him if he saw it, but the bot that Peter wanted could only be picked up on a planetary system where Yondu had already decided they weren't going to stop, and it wasn't worth it to bring that argument back up. "I'm in my bunk," he called back, not bothering to keep the irritation out of his voice. "What do you want?"

The hatch opened inwardly with a bang. Yondu entered, flourishing a bag he was holding in one hand, grinning his sharp grin without a hint of malice. "Quit that sulkin'! It's your birthday!"

"My what?" Peter swiveled to put his feet on the floor. He knew what the date was in Terran measurements, but it was hard to believe that Yondu did. Ravagers didn't celebrate birthdays. At least, newly accepted teenage Ravagers who were wary of ridicule didn't. "Hey," he said, suddenly noticing something very familiar about the satchel that Yondu had brought in, "is that my backpack?"

"That it is!" He tossed the bag to Peter and pulled up a stool by the bed. "Universal calendar tells me you just clocked your seventeenth Terran year. Go on, open it!"

There was more than half a chance that this was just some lookalike child's backpack that hadn't even come from Earth, but Peter dared to hope. Even if it was empty, it would be great to finally have a memento from home aside from the clothing he had been wearing that day and one picture of David Hasselhoff. He turned the bag over in his hands. "I thought the guys stole it. It was gone a couple days after I got here, and I never saw it again."

"Eh." Yondu shrugged, almost apologetically, though he still had that excited look on his face. "Weren't too hard to find once I went lookin' for it. I 'spect them fools tried to sell it an' forgot all about it when it turned out it ain't worth half a unit all told."

Peter allowed himself a small smile and unzipped the backpack's main pocket. He reached in, and his heart skipped a beat. "My Walkman."

"Music player, ain't it?" Yondu was clearly pleased with himself.

"Yeah. Yeah, I mean, there's no way it works anymore, but…" He hit the eject button and his mother's handwriting appeared. He held back a choking sound. "The tape's still in it."

Yondu motioned impatiently. "Try it out, boy!"

Peter closed it and pressed play to oblige him, and the strains of "I'm Not in Love" whispered out from the headphones sitting beside him. Stunned, he put them on, adjusting for the years of growth his head had undergone. It was the last song he had listened to before he left Earth. It was real.

"How 'bout that?" said Yondu, cackling in delight. "I replaced the parts you had in there what was likely to fall apart. Oughta keep for life, now."

Peter stopped the tape and took the headphones off. "Thank you." He couldn't say more than that. Even those two words were more sentimental than Yondu liked, but they couldn't go unsaid. Not when he had his mother's music back.

Yondu waved off the gratitude as if he were swatting a fly, and scooted his stool closer. "What else is in there?"

The answer, when Peter reached back into the bag, was a battered binder that closed with a velcro tab. The front cover had a Sonic the Hedgehog image, and Peter's name in permanent marker. He snorted. "It's a Trapper Keeper. For storing homework."

"Home...work? What d'ya do with that?"

Peter opened up the binder and removed a handful of yellowing pages bearing unfinished math problems. "This!" He took a lighter from the storage over his bed and ignited the bottom corner of the papers, holding it at arm's length while Yondu hooted and clapped. Peter blew out the flame as the ashes floated down to the floor. "Thought I would never get a chance to do that."

The next thing to come out of the bag made Yondu's eyes light up. "Ain't that cute!"

Peter smiled at the troll doll. "It's just a dumb toy kids collect on Terra. You can have it for your console if you want." He held it out.

Yondu leaned forward and cuffed him lightly on the head. "Didn't I teach you nothin', boy? Don't you go givin' anything out for free!" He sat back and nodded firmly. "If I want that dumb toy I'll steal it from you myself, fair and square."

"You can try," Peter shot back, stashing the troll back in the bag. There was one more item in there, which he knew by its shape when his hand brushed against it. He didn't take it out. Instead, he picked up the headphones again and said, "Mind if I…?"

"Yeah, you go 'head and play your Walkerman," Yondu replied easily. "I got stuff to do." With a careless wave behind him, he was gone from Peter's bunk as swiftly as he had come in.

He must have known about the package that was still in the backpack. If he had fixed the Walkman, he must have taken inventory of the rest of the contents, too. But when Peter finally held the little box in his hands, it was still wrapped up like it had been that night at the hospital, and Yondu hadn't so much as asked him about it.

You go ahead and open it when I'm gone, she had said. Peter put on his headphones to finish the song. It was his birthday. He didn't have to unwrap his present if he didn't want to.

Nebula parted ways with the Quadrant when she learned that they were headed back to Berhert. As far as Peter knew, she didn't have any real destination of her own yet, but she was certain that Berhert had nothing for her, and he supposed she was right.

Rocket was certain that he could still repair the Milano, though, if it didn't get hit by scavengers first, and Peter couldn't just give up his faithful ship when there was a chance to salvage it. They landed in the remains of a swath of forest they had destroyed in their first visit here, and Peter had a nasty shock realizing that native trees had died and native creatures had lost their habitat thanks to the Guardians. Thanks to him and Rocket, anyway. He considered bringing it up with him, but one glance in his direction told him it wasn't necessary. The raccoon was silent and grim, casting his eyes above and all around him, taking in the damage.

The good news was that the Milano was in much the same condition that Rocket had left it. He started work right away, accepting help from everyone who offered but delegating the tasks himself. Peter promised to do his fair share later, but the first thing he asked Rocket was, "Do you have anything like a sawblade? Something that makes a clean cut but doesn't sear the surface?"

Rocket suggested Gamora's sword, but when they had finished yelling at each other over that, he produced a blade with a rotating chain from the Milano's tool supply. "What's it for?" he asked, sounding far more curious than wary.

"Demonstration," said Peter. He found the nearest felled tree, one which would have been too big to get his arms around when it was standing. He used the chainsaw to cut through it, leaving a flat-topped stump. It was exactly what he had wanted. "Hey Groot," he called, and then added, "Hey everyone. Take a break. Come over here."

Groot ran over and immediately hoisted himself onto the stump, sitting on the edge with his legs splayed out and the pattern of concentric circles under his hands. Peter crouched next to him and touched the circle in the center as Gamora made her way over and stood behind him. Mantis was next, dropping to his level and hugging her knees, and then Drax took a place beside her and Rocket hopped up on the surface with Groot.

"What are we looking at?" asked Gamora.

"When I was a kid," said Peter, "we learned about how trees get these growth rings inside. There's a new one every year, so you can count them to find how old the tree is."

There was a pause while everyone's eyes stayed fixed on the stump. Even Groot looked like he was trying to count them. Peter got as far as twenty, lost it, and stopped trying. "Anyway, I thought that was really cool. Humans have to look at calendars and tell each other when they get a year older, but trees have it all written right in their wood." He looked at Groot. "It doesn't take a whole year for you, but you're still growing just like this tree did."

"Quill," said Drax, sounding alarmed. "This is a terrible idea."

Peter resettled his position, looking up at Drax. "What's terrible?" he asked, then considered and added, "What idea? I was just talking."

"We can't cut Groot in half to see if he has growth rings. It might injure him."

Gamora snickered. Rocket put his face into his hands and sighed. Groot looked back and forth from the stump to Drax and asked, "I am Groot?"

"Dude, I'm not going to cut him in half!" Peter picked Groot up from the stump and held him in his arms as he got up to his feet. "It doesn't even matter if he has rings inside. What matters," he said, meeting Groot's wide shining eyes, "is that changes happen, but some things always stay the same. Before you know it, you might be the one picking me up. But you are Groot."

The little tree smiled. "I am Groot!"

Rocket started laughing. "You know what he just said?" he sputtered. "Ahahaha...he said...hehe..."

Peter couldn't tell if it was the contextual clue, or if he had heard something new in Groot's voice, but he didn't need Rocket's translation this time. "He said, 'I am Groot.' Didn't you, buddy?"

"I am Groot," came the affirmation.

"He is Groot!" said Mantis, as if suddenly discovering something marvelous. Drax nodded and echoed her.

Gamora reached across the stump and placed her hand on Groot's back. "You'll always be our Groot."