The first time Leo shows up in the Lair, it's because Mikey and Donnie ran into him on their way home from April's. Mikey drags him along and Leo complains lightheartedly, using their names.

He explores each and every room on the tour. Mikey and Donnie may have been tired, but they didn't stop him.

The second time, Leo decides to try out Mikey's hammock and the crash is what alerts the two turtles to his return. Mikey ends up icing Leo's head and introducing him to blankets.

The third and fourth times, he just pokes his head up from the water in the Atrium and watches Donnie and Mikey.

The fifth time, Mikey notices and introduces Leo to comics... sort of... These are quality comics and Leo can read them now!

The sixth time, Leo freezes midway through making dinner with Mikey and darts off back into the sewers.

The seventh time, the only reason Mikey and Donnie are aware Leo was here is the rabbit plush covered in sludge left at the entrance of the Lair. Mikey calls it a nice gift and cleans it thoroughly, before it makes a home in their room. Donnie carries it with their mechanical arms and doesn't talk about it. They don't like gross stuff.

And then Leo doesn't come to the Lair for a month.

The eighth time, Leo just pops up under Mikey's arm as he cooks and he has to shove them both out of the way of the not fully cooked and still liquid pancake. Leo finds it hilarious, but he understands not to do it again.

The ninth time, Mikey gets some warning in the form of a greeting before Leo dives under his arm, joining him on the beanbag. Mikey loves reading comics to someone just as interested in them as him.

The tenth time, Mikey investigates a crash. Leo had startled Donnie by appearing over their shoulder and asking what. Something or some things had blown up. It isn't very clear which is true. Mikey, of course, finds this hilarious.

The eleventh time, Leo is in the kitchen watching Mikey. Mikey ends up teaching Leo the glory of cooking or, at the very least, trying to.

Leo can't cook.

Mikey isn't surprised and simply fixes Leo's mistakes and acts as guiding hands. The food is edible and actually good quality.

Donnie, Mikey and Leo eat every bite.

The twelfth time, April and Mayhem are in the Lair. Leo announces his presence in the kitchen, where Donnie is helping April with homework and Mikey is making some lunch, with hissing.

"Hi Leo," the turtle siblings say in unison.

Leo continues to hiss.

Mikey sighs. It's not overly aggressive, but Leo is on edge enough to hiss.

Donnie rubs the top of their beak, "Leo, meet April and Mayhem. April, Mayhem, meet Leo. He's our neighbour."

"And friend!" Mikey butts in throwing a pizza puff at the doorway. Leo catches it in his mouth, before returning to his hissing.

"And friend," Donnie admits, watching Leo turn back to them, and they smile at him, "April and Mayhem are friends too," Donnie explains, gesturing to each. It doesn't work.

Mikey, however, tries a true and tested method, "Try to give him these! It worked when we first met him."

April looks down at her hand, "A... pizza puff?"

"Yeah! He loves them!" Mikey smiles, going back to cooking.

Donnie doesn't look up from the textbook they picked up, "That is how we gained his trust when we first met him."

April rolls her eyes, "Did he try and kill you like everyone new you two meet seems to?"

"You didn't," Donnie points out, "And, no. Not directly."

April raises an eyebrow, holding Mayhem tightly in one arm as she holds out the pizza puff with the other, "Not directly?"

Leo slowly approaches April and she keeps her attention on the conversation.

"Yeah," Mikey nods, stopping her humming to reply, "The Big Guy was the one attacking us, not Leo! Leo simply tracked us and alerted him to where we were!"

"What have you two been up to?" April asks.

Donnie shrugs, "We did tell you we found the mutant that the humans thought was a sewer monster."

"You didn't tell me he was a small, mutant turtle that you adopted! No offence, Mikey," April barely keeps herself from yelling.

Mikey shrugs, "None taken. You're not much taller than me."

"Besides," Donnie interrupts, "it was the Big Guy that got spotted by humans."

"Does this 'Big Guy' have a-whoa! He's fast," April lets out a laugh in surprise as Leo darts to sit by Donnie's feet.

"Yep!" Mikey agrees, bringing over the pizza she made, "Leo's super fast!"

April shakes her head, "That's super cool and all but who is the 'Big Guy'? Did you save Leo from MeatSweats or something?"

Mikey scratches the side of her shell, "The Big Guy is Leo's big brother, we think."

"You think?"

"Leo grew up deep in the sewers," Donnie sighs and hands the turtle a slice of pizza, which he takes and happily begins chewing on it, "with the Big Guy."

April's eyes widen and she smiles down at Leo, "He grew up pretty isolated, huh?"

Donnie nods and Mikey speaks up, her voice quiet, "He was literally skin and bones when we first met."

Lunch is quiet as they eat, but it livens up when Leo steals Donnie's slice. Donnie may have acted offended and failed to wrestle Leo into submission, but Mikey and April could tell Donnie wasn't upset.

Leo clearly understands that, especially when he steals Donnie's next slice too.

The thirteenth time, Leo perches on Donnie's desk and watches them work for two hours.

The fourteenth time, Mikey wakes up to Leo sniffling in the corner of his room. That night ends up being Leo's first sleepover.

The fifteenth time, Mikey reads their comics as Leo swims laps in the Atrium.

The sixteenth time, Leo finds Mikey crying in the corner of her room. Leo quickly realises that Mikey doesn't want to be touched at first, but accepts the sudden hug from the younger turtle, once she has calmed down.

The seventeenth time, Leo just shows up and joins Donnie and Mikey in their blanket nest in the living room.

The eighteenth time, Donnie finds Leo hidden under a table. They sit under there with Leo, letting him rest his head on their shoulder.

The nineteenth and twentieth time end with Leo standing triumphant and devouring the pizza reserved for the winner.

The twenty first time, Leo shows that he is very good at finding handholds and climbs to the top of the Atrium, much to Donnie's worry. They hover beside him the entire time and watch him freeze up as sunlight hits his skin.

The twenty second time is movie night and, afterwards, Leo learns that Donnie's shell is soft.

And every time he visits after that, Leo slowly carved out his place in the home. An old storage room eventually fills up with Leo's stuff.

Then, one day, Splinter spots them introducing Leo to pillow wars.

It's... interesting...