Disclaimer: All characters are copyright of DC. No monetary profit is being made from the writing or distribution of this fic.

Chapter 1

Undercurrent

There was only one the first time. Tim remembered that very clearly. He was seven, clambering around on the rocks that jutted out of the bay like sharp steppingstones. There was no one watching from the house above, perched at the top of a wall of gray rock. Jack was out, and there was no one else to care. Even if there had been, they wouldn't have seen, not with the house's multifaceted eyes blinded by drawn shades. So there was no one to come running, no one to notice at all when an unexpected wave knocked him flat into the roiling surf. The shocking cold tore a startled gasp from his throat, then everything was drowned in white-capped foam and the roar of the surf sucking away from the rocks. It was thunder, crashing down all around him, rolling over him. Arms and legs tumbled helplessly, and unable to keep his head above the towering swells, the endless, head-on rush of waves dragged him under.

It wasn't always so turbulent—sometimes the water rippled seductively as silk—but the wind was fierce in the bright sky that day, sharp with the promise of storms to come, and it thrashed the waves against the shore. Out by the rocky points, the water was deep, dropping down into storm-carved stone basins, and the current took Tim with it, sucking him down. Salt stung his eyes, burned his nose, and he choked, air bubbles escaping all at once. He could see the air above him, beyond the foam-capped barrier that seemed progressively farther away. He could see it—bright streams of sunlight breaking the surface above, turning the sea an aquamarine blue—but he couldn't reach it. There was too much water pressing him down, rolling over him.

Then something glittered off to his right, a blue shimmer catching streams of light, and there was another boy in the water, swimming toward him. Wisps of black hair floated around brilliant blue eyes as the older boy drew closer. Tim remembered that too, despite the hazy, oxygen-less film that clogged those memories in the water. He remembered that startling blue, and the way the boy smiled as much with his eyes as with his mouth.

The thunder of the waves above fell away. In its place, there was a deafening silence, as though even sound had been crushed down and forgotten, like everything lost in the depths. It was fitting that it should be in that place where lost things lived, suspended in space, he should have such an impossible meeting. Impossible, because there couldn't possibly have been anyone else down there.

Addled as he was, it took Tim a second to realize the boy was mouthing something, like It's okay or Hold on. Then strong arms wrapped around him, lifting him up, breaking him free of the current that had him trapped. The light got brighter, closer—he could almost feel it. Then, finally, the water fell away, and he sucked in air, filling his lungs. The roar and crash of waves once again pounded at him, but it felt good, better than being below them, and with those strong arms under him, wrapping around him supportively, it also felt safe. His rescuer half lifted him, half pushed him up onto a shallow rock, still choking and gasping. He caught at the crags with numb fingers, entire body heaving as the last dredges of seawater were dispelled from his lungs. As he regained strength, the supporting hand on his back started to slip away.

"Wait!" Tim whipped around, scrabbling for purchase when the motion nearly dislodged him from his rock, but the strange boy was already disappearing silently back under the surface. It was only then, with the brilliant sun backlighting him in the water, glittering off a myriad of blue scales, that Tim saw the fins. Beautiful blue fins like fine gauze.

Even blinking blearily through salt-sore eyes, that was the image that would stick with him for years.

The whole experience should have frightened him, should have made him a little more cautious in his explorations. If anything though, it had the opposite effect. If he'd known, Jack might have been a bit worried when, for the next month, Tim would run out into the water on the edge of the deep pools and stick his head under the surface looking for mermaids. There were never any around, not the smallest glimmer under the waves, and as the days wore on he began to despair of ever seeing his rescuer again.

But he never forgot, and he never stopped looking.

It was Jack who planted the idea one day when Tim came home sopping wet for the fifth time in a row.

"No, no, no," Jack said, and Tim halted guiltily in his tracks, daring to slide a sideways glance at the man standing above him on the second-story landing. "You're getting water everywhere." The puddle at his feet inched a little wider under the scrutiny. Tim curled his toes and tried to look as repentant as possible.

"Honestly, Tim, why do you have to go down there so often? It's dangerous! I've already lost your mother to that ocean, and now the Lasky's child disappearing and half the town blaming it on merfolk and strange marks..." Jack sighed, leaning against the banister. "That witch certainly isn't helping matters, going on about them the way she is. The last thing I need is you down there, looking for the forsaken creatures!"

"Witch?" Tim asked, perking up.

"Now don't you go getting ideas. She's a snobbish old thing, holed up in that house of hers more often than not—if you can call that old thing a house, what with all those–" Perhaps realizing that this conversation was not going at all where he wanted, Jack stopped mid-sentence, scowling. "Well, what are you waiting for? Go get dried off!" Tim didn't have to be told twice. He scurried the rest of the way across the floor and into the bathroom.

Of course, the reprimand did nothing to dim his anticipation at the prospect of talking to someone else who might know something about the merfolk, witch or not.

It didn't take Tim long to pick out a day Jack was safely off on business to sneak out of the house. The merfolk in the bay were something of a sore subject around town. Half the townspeople thought speaking of the creatures brought bad luck, and the other half thought they were to blame for empty nets and summer storms and backed-up pipes. It was no use talking to anyone about the merfolk. But they were all willing to talk about the witch and the nest she called a house.

That was all Tim needed.

He didn't have much trouble finding the witch's home—if he had any at all, it was because it blended so well with a stand of trees just off the bay, removed a good distance from the neon lights of the town. It was a small cabin, or it had been, now weathered and dilapidated and held together more by the vines that wrapped around its entirety. Salal and Huckleberry bushes shouldered close to the outer walls, as if the forest was literally growing up the sides. Through the sheets of ivy that hung across the open door, Tim could just make out bits of the room beyond. Glass tanks crusted windowsills and tabletops and every other conceivable surface, full of Feather Ferns and Maiden's Hair and plants Tim had never seen before.

The woman sitting cross-legged in a chair at the table wasn't what he had expected. She had long, auburn hair, tied up with strands of pearls and decorated with a crimson spiral shell. Green, high-heeled boots clung to her feet and wrapped up around her calves.

Realizing that he was hovering awkwardly outside the door, Tim reached up to sweep the vines aside, attention on the woman beyond. He didn't immediately realize there was anything wrong when the vines caught around his wrist instead like leafy green manacles, thinking he'd simply snarled them. Surprised, he tried gently shaking his wrists free from the foliage. It didn't work. Neither did jerking on them. It only made matters worse. The harder he tried to jerk himself loose, the more the vines pulled back, until they had him stretched up on his toes, hopelessly tangled. It was only then, with little creepers running in spirals down his arms and into his hair, that he fully appreciated the mess he'd walked into. More coiled possessively around his midriff, up under his shirt. Tim squirmed under the assault.

It was the witch who finally came to his rescue.

"None of that now, he's a guest." A flick of her eyes—emerald eyes, startlingly green—was all it took for the vines wrapping around his arms to unwind. "Why don't you offer him a seat?" No sooner had his feet touched the ground than those same creepers began herding him forward, coiling warningly against his lower back. There was no going back at that point, so Tim took the hint before they could start dragging him and sat down in the chair he was offered. It, too, was crusted with vines, twined around the backrest's spindles and curling around the arms. There were little leaves sticking out from under the seat.

"Are you the witch?" he asked, when a minute passed and she showed no sign of abandoning her task. She wasn't what he'd expected, certainly not old like Jack had made her out. She looked beautiful and young, from the tips of her lacquered fingernails to the high arch of an eyebrow.

"Call me Ivy." At last she looked up, truly turning to face him for the first time, and Tim didn't like the sudden spark of interest that lit her emerald eyes. He felt suddenly like a bug—a particularly interesting bug—tangled in a woody web, and the spider had just noticed him.

"Well, aren't you a pretty one?" The sharp tips of her fingernails slid along his jaw thoughtfully, caught under his chin to urge him to lean forward, closer to those appraising eyes. "Yes, you'll do juuuust fine." Tim had no doubt that if she wanted to, she could wrap him up on the spot—tie her vines so tightly around him that he'd be nothing but a living cocoon. The sinister rattle of leaves rustling around under his seat didn't help. Then, just as suddenly, she turned away, back to the aquarium and the feathery plant she'd been babying. "What is it you want?"

"Tell me about the mermaids in the bay. Do they really steal children?"

"Mermaids." She mused for a moment over something in the water. "Stories, is that all? I will not be made a source of entertainment for you and your friends. If that's it, you'd better run back home, little boy." Tim shook his head frantically.

"Not stories. The truth. I met one." At Ivy's skeptical glance, he continued. "I fell into the bay. One of them pulled me out."

"What did it look like?" she asked, still seemingly unimpressed. Tim started to describe the boy, his eyes, his hair, the way he remembered blue scales in the sunlight, but Ivy cut him off impatiently. "His shoulders. Was there anything on his shoulders?" Tim tried to think back, to remember if there'd been anything. Something about the way the light had hit him…

"Yes. There was some kind of silver mark. I didn't get a good look."

"So you did see one." He had her attention now, the full weight of those green eyes. The little plant in the aquarium waved its feathery tendrils in the water, temporarily forgotten. "And you came to me. How fortuitous."

She believed him. Somehow that alone seemed to take a weight off his shoulders. Someone believed him. He wasn't alone.

"But I haven't seen him again. I've looked and looked."

"Useless. They don't interact with humans."

"I want to talk to him, at least thank him."

"But you can." She smiled, a wickedly knowing smile, hushing him with two fingers against his lips when he leaned forward excitedly. "Now that's better. I can work with this." The hand at his mouth moved to brush feather-like over the lashes of one eye before burrowing thoughtfully in his hair—touches Tim bore with a measure of patience. Her voice grew distant. "Perfect. Just the same coloring. I wonder… He does seem to have a thing for adoption." Something in the way she touched him, looked at him, made Tim feel like a mirror—a mirror in which she saw someone else. Perhaps sensing his confusion, she smiled more reassuringly. "I'm going to help you meet this rescuer of yours. I'm going to show you how to get his attention." Reaching back into the aquarium, she pulled a gold piece from the bottom Tim had initially thought decorative and pressed it into his palm.

"This will help me see him again?" Tim asked, skeptical. It was just a coin. A little wet, a little cold, but nothing special.

"Hush. You wanted to thank him, right? Put that where he'll find it. And if it's seeing him again, I don't think you'll have to worry about that." She muttered something about having a type.

Tim nodded and pushed the coin into his pocket. He started to stand, to thank her, but one of the vines wrapped suddenly taught around his arm. Ivy pushed off her chair to crouch in front of him, hand going to cover the vine. Those green eyes riveted to his.

"Promise me you'll come back. Come talk to me about your little mermaid friend. I want to hear all about it." Her fingers slid under the leafy manacle encircling his arm, carefully coaxing it free.

"Yes." The word came out slow, uncertain.

"It's a promise. Now one last thing…" She leaned forward, free hand going to cup the back of his neck and keep him from leaning away. A jolt of panic raced down his spine before fizzling out. He should have felt trapped, should have been worried she was so close, but with the breath of her words fanning against his skin, he felt only… dizzy. "My payment." Then her lips sealed against his in an acidic kiss that ate away at the world until there was nothing left but distant intentions, like stars far off in the darkness. The dizziness pitched high into acute vertigo, and he was falling, falling forever, but he couldn't move to save himself. He stood paralyzed by Ivy's touch, the pull of her poisonous lips, the feel of her tongue on his, a discomfort he couldn't escape. He could feel the points of her fingertips pressing against the vertebrae at his nape and the brush of creepers sliding across his shoulders, curling in his hair—could feel them, but do nothing. They pressed up against his back, steadying him for Ivy's pleasure as she took what she wanted. He might've blacked out for a second. It was the only way to explain that worrying lapse. When he came around, Ivy was smiling down at him, a hand tight around his upper arm to keep him on his feet.

"Careful now," she said, steadying him as the vines withdrew and he took a shaky step backward. He blinked, taking in the aquarium-lined counters and cabin walls, remembering where he was and how he got there. The kiss had only lasted a few seconds, but he'd somehow lost days.

"I'm sorry. I should go." He put a hand to his head, as though the weight might keep the room from spinning. It didn't. He couldn't explain why his knees felt like buckling or his eyes wanted to slide closed.

Ivy was more than understanding. She saw him to the door, parting the curtain of vines for him and seeing him off with one last ruffle of her hand through his hair. He heard her pleased whisper behind him as he left.

"This may be the beginning of a very rewarding relationship."

Tim wasn't actually able to follow through with Ivy's suggestion that day. All the way home he felt dizzy and lightheaded, and he probably worried the housekeeper by collapsing into bed in the middle of the day and sleeping through dinner. He didn't remember anyone trying to rouse him, despite later accounts to the contrary—didn't remember large pieces of his encounter with Ivy. Whatever had possessed him, he felt fine when he finally woke up the next morning.

So it wasn't until later that next day, he ran down to the beach to put Ivy's trick to the test, leaving the coin out on one of the rocks, just clear of the waves. Then he clambered up on one of the boulders where he could just make out the gold speck glimmering in the sunlight below, and settled down in a crag to watch…

And watch. And watch. Until at some point in the late afternoon, the sudden cry of a gull startled him from a nap he'd never meant to take. He immediately looked down where he'd left the coin, but of course, it was gone.

Assuming the waves had washed it away or some intrepid bird had claimed it for a prize, he trekked home that night, disappointed and hungry. He didn't think on the missing coin again until the next day, when a seashell suddenly appeared on the same rock when his back was turned. It was impossible to miss—a bright white on black rock. As he got close, he could see that it was a Wentletrap shell, light tan with pure white ribbing. All around, as far as he could see into the crags below, the water was clear and empty, but it didn't stop him from breaking out in a wide grin. He stood up on the rock and waved the shell in the air, knowing that somewhere out there another boy was watching.

Oftentimes thereafter, when the sun was bright and the water clear, Tim would put bright coins out on the rocks. He never saw them disappear, but they were always gone when he turned around. And sometimes, when he was busy looking for crabs, watching them scuttle away when he lifted up stones on the beach, exotic shells in brilliant colors would appear on the rocks where the coins had been. Useless as it was, on those occasions, Tim would splash out as quickly as he could in the hope of catching sight of his invisible friend. He never could make it in time, instead waving thank you to the empty sea.

Ivy was always willing to hear about it though. She was someone who would listen, someone who wouldn't laugh at him or shoo him away for telling stories. She always asked him to come back, and he always did.

He always did.

Author Note: And thus Tim begins his stalking days early. This is my addition to the little pile of mer!Tim fics haunting Tumblr, because it was driving me crazy that none of them were longer than 1000 words, and while I may not be qualified to write good mer-fics, I have yet to find a longer mer-batfamily story (so I achieved my goal). Definitely a change of pace from my last story. Tim is so cute when he's young! And happy. But he won't be staying this young for long.

Ivy is totally off character, isn't she? She hasn't shown up in any of the Robin or Nightwing comics I've read (which is around 98% of them), so I was having trouble gauging her character. Obviously her kisses aren't poisonous here, but they are still bad news. While brainstorming ideas, we were totally stuck on water-based villains. I even thought Penguin at first maybe because the merfolk were messing up the fishing trade or something, but I really didn't want to work with that character. It was my beta's idea to use Ivy as a seaweed witch, and the idea was just particularly attractive (though somehow she still ended up using ivy). The entire time I was writing this, I swear, I was battling Ursula lines: "Oh, there is one more thing. We haven't discussed the subject of payment. You can't get something for nothing, you know."

Huge round of applause for my beta, Schnickledooger, for putting up with me and my terrible writing (and my complaining about it being terrible).

Oh, notes:

1. Gold is the coin's color, not its material, though I'm sure our mer-friends prefer gold, seeing as how it doesn't rust and hardly tarnishes, unlike silver.

2. The Lasky's child is Mike Lasky, also known as Dodge. (Robin 156-ish, or Teenage Wasteland)

3. The shell in Ivy's hair is a Kiener's Delphinula from the Philippines. If you look up pictures, it's quite pretty.

Next Time: We're jumping forward in time by several years. Tim finally learns his rescuer's name and meets more of the family... the hard way. But when his involvement with them causes rifts in his own family, which side will he choose?