"Stupid. Damned. Sphere." Leo punctuated every word with a blow of his hammer to an unfortunate metal sheet. In the end, he gave up and sank to the floor, holding his head in his hands.

It was just so frustrating. The designs of the metal crane arm to snatch Percy and Annabeth out of Tartarus wasn't even started yet, and deep down Leo knew that it wouldn't help in any way even if he did manage to construct it. Even his research and experiments on the Archimedes sphere wasn't making any progress. The sphere won't budge for Leo, and it doesn't respond to any experiment. The Archimedes sphere had mysteriously shut down after their little excursion at the entrance of Tartarus where Percy and Annabeth fell, and hadn't started up Argo II was making steady progress towards the spine of Italy where the mountain gods lived, but Leo hadn't made any progress at all at the only thing he was good at.

He started to show up less for meals, instead choosing to tinker away furiously at the Archimedes sphere during meals, with the occasional sandwich clenched between his teeth. He became thinner, paler, and less like his usual cheery self. And the Archimedes sphere still won't respond.

It was on the day before they reached the spine of Italy when Leo finally broke. And his friends finally noticed what they had been missing all along-Leo's presence.

Leo was once again in his room, with grease in his hair, oil on his face and in his fingernails, plus soot covering most of his body. He hurled the wrench across the room only to have it crack a window and fall out of the ship. Leo hoped that it wouldn't crack some unfortunate mortal's head.

"Argh!" Leo kicked the table, relishing in his little tantrum. "I can build a huge trireme in a matter of months but I can't even make this sphere at least explode?! What kind of mechanic am I? Dad must be so proud of me."

Leo rolled his eyes at himself. Seriously, what had made him come to the point of madness by talking to himself? First sign of madness: talking to yourself. But he didn't care. The Archimedes sphere had managed to wear his nerves down until he was sure that he didn't have any left. He slumped against the wall, feeling useless and helpless. This felt just like the night his mother died. He'd also been the one to cause it, and he'd been powerless to save her too, just like he'd caused Percy and Annabeth's fall into Tartarus by opening that fortune cookie. He wished that he'd just burned the cookie up when he'd had the chance.

Unknowingly, he started to cry, slumping against the wall.

Frustration could do that to people sometimes.

"Leo?" the door creaked open. Leo frantically wiped at his eyes, trying to look busy as Jason entered the messy room. Jason couldn't help widening his eyes a little at the scene before him. Tools were scattered everywhere while grease and oil were splattered on the floor. The walls were charred, as if something had exploded in the room multiple times. One of the windows was broken. And standing in the middle of the room, in all his glory, was a very disheveled Leo Valdez who was tinkering away with the Archimedes sphere with his back to Jason. Queerly enough, Leo's thin body was shaking like a leaf in the wind.

"Leo?" Jason called again, unsure whether Leo heard him the first time. Jason knew how focused Leo can be on his projects, and that could rival Annabeth. He'd been nearby when he'd heard Percy's conversation with Annabeth, and he had to duck into the toilet to hide his laughter lest Percy finds out and takes offense.

He tapped Leo gently on the shoulder. Startled, Leo whirled around by instinct before turning away just as fast to hide his tear tracks. But Jason noticed anyway. He frowned, the scar on his lips curving along the line of his mouth. "Leo, what's wrong? You know that you can tell us, right? We're your friends."

Leo didn't answer. He didn't trust himself not to start bawling when he opened his mouth to speak.

Jason mistook the silence. "If you don't want to talk, it's fine." He said a little more roughly than intended.

"What's up with using that tone with Leo?" Piper asked, poking her head inside. "Nico's waiting. He said that there will be more problems to address when we reach the spine of Italy. Come on, guys, let's go."

Leo stuffed the Archimedes Sphere into a drawer, suddenly fuming. Jason should know better and give him some privacy. And he really didn't want to go out and face everyone in this state.

"Guys." Nico himself came in. "Would you mind hurrying up a little? What's holding you up?"

Piper pointed at Leo. Jason just scowled and said, "Leo won't tell us what's wrong."

Nico frowned. "Could the two of you please go out for a while?"

Piper obliged, understanding that the situation might not be the best for her and Jason to interfere. Jason paused at the door for a minute, gave Nico a threatening glare that said: Hurt him and you die. Before exiting the room.

Nico didn't start to interrogate Leo, like Leo had predicted, instead sat down on one of the relatively cleaner sheets, crossed his arms and waited.

Twenty minutes passed like that, with Leo taking out the Archimedes sphere and continuing his experiments, and Nico didn't even move, though he'd picked up a scrap of metal lying nearby and started to fiddle with it. Apparently Nico had ADHD too. Other than that, however, Leo had almost forgotten about Nico's presence.

"Say," Leo couldn't help but speak up. "Don't you have better things to do than sit there and wait for a useless person to open up?"

Nico uncrossed his legs. "You're not useless." He said quietly. "No one is, even if they think they are."

"Fine," Leo snapped. He really didn't like this guy trespassing on his safe haven and his privacy. "I'm not useless. I can save Percy and Annabeth from Tartarus. I shouldn't have to rely on that stupid cookie to save Frank and Hazel. I wouldn't have been the seventh wheel. This war would have ended long ago. My mom-" his breath hitched. "My mom would still be alive."

Nico got up and touched Leo's shoulder. "Nobody is perfect." He said softly. "I can't save Percy and Annabeth either. I want this war to end too. My mom and sister died because of me."

Leo stared at Nico. This guy hated physical contact, and he was even more reluctant to tell others about his past, so why was he being open to Leo all of a sudden? As if he could read Leo's mind, Nico said, "And don't you dare tell others this. I just told you because you needed it."

Leo scoffed. "Come on, are you joining Team Leo too?"

Nico allowed himself a small smile. "Can I?"

Leo frowned comically, putting one finger on his lips. "I suppose that we've got space for one more."

Nico smiled, then spotted the sphere on Leo's worktable and the designs of the giant crane arm. He frowned, pointing at the designs. "I thought you were joking about that."

"I wasn't." Leo admitted. "I can't prevent them from falling in, but I should at least be able to get them out."

Nico shook his head. "They won't stay in one place long enough for the arm to pick them up. Besides, who knows what monsters will come up with them?"

Nico's logic made Leo feel silly for spending hours over that thing.

"And about the Archimedes sphere…" Nico continued, oblivious to Leo's embarrassment. "Try mixing it with a melted down combination of Imperial Gold and Celestial Bronze. It might cause an explosion though."

Now Leo felt stupid for not thinking of that earlier.

Nico barged on, heedless to Leo's self telling off.

"Or you could mix a combination of liquids that mix and one that causes an explosion. Who knows, the outsider could maybe be the one to make the whole thing work."

Leo gawped at Nico, who left the room, calling out, "Next meeting, same time, tomorrow. No one's going to get you again if you forget!"

Turning his attention back to the Archimedes sphere, he tried out Nico's second theory. The first thing he saw was beautiful red. Then the sound reached his ears in a massive bang.

His room was partly demolished, but Leo had never felt happier. The Archimedes sphere whirred in his hands and the clicking started. It was Morse Code: You have succeeded in activating the Archimedes sphere. Please give the next command.

Grinning broadly, Leo punched in the numbers and got to work.

Thanks, Death Breath. Leo thought in the back of his mind.

The next day, Nico announced the grim news to the crew of the Argo II at the meeting Leo had finally remembered.

The mountain gods will cause trouble.

But Leo wasn't afraid. Not when his friends were by his side.

The end

So how do you think of it? I don't know, I wanted it to be as canon as possible but…

Anyway, it's finished!

Special thanks to: Phoenix McLean and Ercole Solace, the friends that still make me smile at the thought of them.