They felt their way into the conversation slowly, as Emma brought tea and blankets. The boys ended up all sitting on the floor; Splinter's sons seemed to think that was completely normal, and while David pulled away from their touches, he allowed them to surround him in a protective semicircle.

"So who names their kid 'David'?" Mikey asked.

"I'm named after my great-great-uncle," David replied.

"Your what?" said Leonardo.

"You know, my mom's dad's mom's brother," David said, but the other boys just looked baffled.

"What's with the cat?" asked Raphael.

"Snowflake is my service animal," David said, and scratched her ears. "I've had her since she was a kitten."

"What are you sick with?" Leonardo asked.

David sighed and played with his mug. "I have a thermoregulatory disorder, a problem with synthesizing vitamin D, and a very unusual form of fibrodysplasia ossificans progressiva. Plus I'm diabetic."

The boys looked at each other. "Kurikaeshite itadakemasuka?" said Leonardo.

David just blinked at him a moment before realizing he'd been spoken to. "Huh?"

"Kurikaeshite itadakemasuka."

"Uh…"

Leonardo's face fell. "You don't speak Japanese?"

"Why would I speak Japanese?"

"It's where we're from," Mikey said. "We read manga and eat donburi and we're, y'know, ninjas."

The corner of David's mouth turned up. "Okay, this part is a joke, right?"

In response, Leonardo reached over his shoulder, drew a long sword from a holster on his back, and lay it across his knees.

David stared at it. "Have… have you had that the whole time?"

"Of course," Leonardo replied.

David ground the heel of his palm into his eye. "I think I'm a little overstimulated." He rested that way a moment, then said, "But you guys are FOP too."

"What?" said Mikey.

"Fibrodysplasia ossificans progressiva," David repeated. Sitting up, he reached out to tap the hard ridge over Raphael's shoulder. "A disorder of abnormal bone growth."

The boys looked at each other. "We're turtles," said Leonardo.

"Right," said David, "FOP 'turtles'."

"No, actual turtles," Leonardo said slowly.

David stared at him. "You're not serious."

Leonardo shifted, sitting up even a little straighter. "Where do you think we came from? We're turtles, only mutated to be sort of like humans."

A smile began to creep across David's face. "Excuse me?"

"There was an accident, and we fell into the sewer with a canister of glowing green ooze, and it mutated us."

David burst out laughing. "Oh my god, it's like you've never heard of Occam's Razor."

Leonardo drew back. "What?"

David wiped at his eyes. "Occam's Razor. The simplest explanation is usually the right one."

"Okay," said Leonardo, "but Sherlock Holmes. When you've eliminated the impossible, whatever remains, however improbable, must be the truth."

David looked at him with amusement. "So really, you're going with mutated turtle over rare but well-described medical disorder?"

"Holy crap," Raphael said suddenly. "You're Donatello."

David blinked at him. "Who's Donatello?"

Raphael was leaning forward, staring at him intensely. "You are."

"Let me rephrase that," David said coolly. "Who is Donatello?"

"He's -" Raphael pulled back. "He's a guy I used to know. Smart as fuck but condescending as shit."

"Well, I never met you before today," David said, "so you must be thinking of someone else."

Mikey's brow had formed a deep furrow. "Raph, are you talking about your -"

"Shut up," Raph snapped. "Just - just forget it, okay?" Gripping his mug tightly in one hand, he half-turned away from the little group.

"Okay, but wait a minute," said David, who was rarely inclined to forget anything. "Talk about just having met people. Mom. Mom Mom Mom Mom Mom Mom Mom."

"Yes, what?" said Emma, who had been half-listening to the boys while talking to Splinter.

"How could you just have met Splinter a couple of weeks ago?" said David. "You must have known him this whole time."

"Ah…" Emma began.

"Mom…?" David twisted a corner of blanket. "How did I get here…?"

"I -" As much as Emma wished otherwise, there was no avoiding it. "D, I found you in the alley."

"I left you with some kittens," Splinter added, which was absolutely not helpful at all.

David's jaw slowly dropped, while the other boys stared at him in confusion. "He dumped me? I'm a kitten dump?" He jerked his mug, splashing the hot liquid over his hand. "Even Snowflake isn't a kitten dump! How could you not have told me?"

"D -"

"I hate you all!" David shouted, shoving his mug at the nearest brother and struggling to disentangle himself from the blankets. "You're all insane," he said to the other boys, "you're a terrible mother," he said to Emma, "and you -" He turned to Splinter with his most scathing expression. "- are a kitten dumper."

He glared one more time at his assembled family, then stormed into his room, Snowflake trotting at his heels.

A frigid silence fell over the group.

"What the fuck just happened?" said Raphael, holding a half-empty mug in either hand.

Mikey shook his head sadly. "Dude's got some issues."

"I'm sorry," said Emma. "He gets like this."

"It is all right," said Splinter. "It is difficult for everyone." He set his mug down on the table. "Perhaps we should go."

"But -" began Leonardo.

"We will see each other again," Splinter said. He nodded to Emma. "I will be in contact."

"Splinter, wait," Emma said, as he ushered his sons out the window. He paused and turned back to her, while the boys disappeared down the fire escape - or maybe up. Emma couldn't be sure. "Is it really true?" she asked. "Are they literally mutated turtles?"

"They are," Splinter said.

"Can you prove it?"

Splinter thought for a moment. "My knowledge of science is very limited," he said. "But I will show you what I can."

"Thank you," Emma said.

Splinter moved towards the window, then nodded at the bedroom door. "Go to him. It is when children feel most abandoned that they are truly most in need of their parents."

"And what about us?" Emma asked.

Splinter turned to look out at the alley. "For all the mistakes I have made as a father, and all the choices I regret, the accident of having become a father is not one that I would change."

In a single graceful move, he swung himself out through the casement. "I will see you soon, Emma Lamb. Yoroshiku onegaishimasu. Please, take good care of our son."

As the curtains fluttered in the empty window, Emma wished she knew how.