Leo did a double-take and run when Donatello returned carrying several bad-smelling syringes of samples from the body for analysis; he was puzzling over a swab as he walked into the den, which had a strange, purple fluid on it.

"Would it be too much to ask for you to transfer to vials before you came back?" Leo asked from under the stairs, the furthest possible spot from Donnie's needles. "You're making me sick."

Donnie ignored him, and continued to scratch his head over the tiny swab. "I got this off the body—wait… Raph's got the girl somewhere else at the moment, right?" He looked around for the first time. Raph, Mikey, and the little girl couldn't be found in any inconvenient corners, so he put down the samples in his alcove. "It's a pretty simple diagnosis, really. They tried some kind of poison first; when she kept going, they switched to shuriken, and finally a katana. A well-made one, from the quality of the cuts, and very precise. Better than your typical Foot ninja. Probably someone elite—so we can figure Karai authorized it. Or it's a rogue."

Leo came closer now that Donnie held only the swab. "What kind of poison? That doesn't seem like Karai's style."

Donnie raised an eyebrow ridge skeptically. "You met her for about 3.5 seconds, and for most of that we were doing battle. What do you know about her style? This dead woman was just some homeless lady with a ten-year-old daughter, and Karai would've had her assassinated in cold blood. She could've even done it herself, judging from the skill."

Leo shook his head, troubled. "I don't know, Donnie. She showed a commendable level of honor, especially for a retainer of the Shredder." He sniffed, as Donnie held the swab. "Wait a second… I've smelled that before."

Donnie handed him the purple liquid on his cotton swab. "Be careful with it—your skin is more porous than a human's; you could absorb it into your bloodstream. Do you remember where?"

"No—I just remember berries that smelled like this. During my trip."

Donnie squinted at the juice. "It must be some sort of plant poison. I'll run a diagnostic for nitrates and alkaloids." He then disappeared into his alcove; the chem set bubbled and boiled into life. Leo shook his head, then moved towards the training room, where a chink of light shown between the door and the wall, and the sound of training ensued. He spied through the chink, but almost gave himself away by laughing.

Raphael had taken the stick away from "Lizzie" and replaced it with a shinaii; she still didn't seem to be speaking, but was very glad to square off with him. Both he and Mikey had the wooden practice swords Leonardo had started on once they'd specialized weapons; the bamboo shinaiis were something they'd all used, in the early days of their training, to teach them how to use weapons like an extension of themselves and learn the footwork. Leo smiled to see the little girl, dressed in several layers of mismatched clothing, holding the big shinaii with those big, bright, determined eyes. Mikey was sitting down, leaning on the practice sword and watching Raph give a lesson.

"Okay—that was good, but you gotta remember that you're protectin' your torso first—so if you lift the sword up like that after a hit, you're leavin' yourself wide open for a fatal strike. Keep the weapon aligned with the middle of your body."

Lizzie swung up toward Raph's head, and he blocked easily.

"Hey—that would be a good move, if we were the same height. But remember, you gotta advantage—you can swing at the legs, 'cause a' your height, and it'll be harder for me to block," Raph said, helpfully; in response, Lizzie, raising an intrigued eyebrow, swung down and brought his leg out from under him. Raph fell on his shell, lying like an entrée in a shallow bowl. Mikey howled with laughter, and after a moment, Lizzie giggled.

"Like that?" she asked cheekily.

Raph shook a finger at her, chuckling. "Okay—I'll hand it to ya, that was really good. Now how about helpin' Raphi up, huh?"

She did as she was told, and lifted her shinaii again, a willing student. Mikey pounded the butt of his practice sword into the ground.

"Whoa, Raphi—I think Lizzie's wearin' you out, huh big bro?"

Leo felt his smile extend, knowing that they couldn't see him; his brothers could be real softies when they didn't have to be tough or be clowns. He felt Donnie come up behind him and tap his shoulder, waving the swab.

"Hey—I got it! Come see!" Donnie said, with the excitement of someone who believes the explosions in his lab are the only earthquakes on earth. Leo followed him calmly, with one last look into the training room.

Donnie stood aside to let Leo look in his microscope; Leo, however, stared at it doubtfully before scowling.

"Donnie—I have no idea what I'm looking at!"

Donatello wafted it under his nose, moving around excitedly. "It's a mixture—from the berries of the wild cherry and belladonna! That's why you've smelled it—numerous tribal groups around the world use berries from the nightshade family, like belladonna, in rituals, because it dilates the pupils when applied topically! When ingested, the belladonna berries release atropine into the system, which can cause paralysis. And wild cherry contains cyanide!" He said all of this very excitedly, as though he were describing Disneyland. Leo, on the other hand, felt vaguely sick, the smell from the vials of decaying body fluids taken from the corpse didn't help matters.

"Yeah, okay, great—how was she capable of keeping going long enough that they thought a katana was necessary?"

Donnie held up a hand. "That's the amazing part! I think I've obtained from the body a number of mutated lymphocytes—a kind of radiation-induced transformation on a small scale not unlike our own, but controlled and targeted! Her immune system fought the poison and stopped it from attacking the central nervous! Isn't it amazing?"

Leo held up his hands, attempting to calm him. "Don—then where did the mutation come from? All of the ooze was disposed of, and the only other mutants aside from us were a bunch of incinerated dandelions and Shredder, who's dead. Who could control the reaction like this, and why would the Foot want to destroy the result?"

"They could be working for someone—but that's your department," Donnie said hurriedly. "I need samples from the girl, to see if they'd be after her as well."

"You know, it might be just a hunch, but I don't think Raph and Mikey will let you anywhere near her with a syringe anytime soon. Sorry."

Donnie glanced around. "Maybe you should talk to Raph about that."

Leo scoffed. "No way. I'm not pissing him off while he's carrying that stick-totting little kid around. When he's feeling protective, heads roll. Have Mikey help you. I'll take Raph out for one-on-one training—he's overdue."

Donnie smiled, recognizing this indirect help, and his older brother's roundabout way of avoiding watching him use the needle. Leo clapped him on the shoulder.

"April should be here tonight with some research on the kid and what we should do about her. She said something about foster services, though she hasn't made a report. It's gonna break our little brothers' hearts." He moved back to spy on the practice room, leaving Donnie to thrill over dead parts and poisons in his dark alcove.

This time, Michelangelo was squaring off with Lizzie, and he was a fair match given they had about the same speed, stamina, and maturity. Mikey refrained from the fancy acrobatics in the spirit of fairness, but the duel was looking like something a group of Star Wars reenactment newbies would put on and upload to the internet, with some rather dramatic chanting monks in the background. Raphael was laughing his shell off.

"Yes—Obi-Wan has taught you well," Mikey said, as they locked wooden and bamboo blades. "Now you will understand the true nature of the dark side of ninjitsu butt-kicking!"

Leo couldn't take it any longer, and rolled the door further open. "Okay—I don't care what you say, Raph does not get to be Obi-Wan."

Mikey laughed, then tossed his practice sword at Leo. "It's true, dudes. Now, Lizzie, we get to see the true battle of good and evil: Leo as Obi-Wan and Raph as Darth Vader!"

Raph, however, was massaging his shoulder and still recovering from a laughing fit. "Naw, man, I'm too tired to be Darth Vader. And why do I always have t'be the Sith guys?"

"Admit it, bro. You do it to yourself—there's something about the brooding loner bit on the outlaw motorcycle that just doesn't lend itself well to the whole Jedi thing," Leo shrugged, then smiled warmly. "And on that note, we have some training up top to do this evening."

Raph groaned. "You just kicked my ass all over half the upper Manhattan sewer system—now ya want more?" He looked at Lizzie. "You okay trainin' and playin' video games with just Mikey for a while, kiddo?"

She considered him with the utmost seriousness for a moment, before steadfastly nodding. "You're Han Solo, Raphi," she said, with a deadpan expression, before saluting with her overlarge bamboo shinaii.

Raphael grinned despite himself and pretended to straighten his shell like a pair of suspenders. "Yeah. I like that. Just better lookin', right?"

Mikey howled. "April always did wonder why she always had to dream of turtles comin' to the rescue instead of Harrison Ford, dude."

Leo put an arm around Raph's shoulders and shepherded him out. "Just don't switch your fedora to the Indiana Jones hat and we should be fine."

They perched on the rooftops at sunset, when the shadows are most pronounced; the sky glowed the same deep red of the dragon kanji that had heralded a murder earlier that day. Leo looked at his brother seriously.

"That kid is acting strange for someone whose mother was just killed right in front of her."

"Oh, really?" Raph asked, raising his skeptical eyebrow ridge. "Your mother ever get killed in front a' you?"

Leo frowned. "You know very well our mother wasn't killed in front of us, and even if she had been, we wouldn't remember."

Raphael drew closer to his brother's face. "Then how the hell would you know what someone's supposed ta act like when somethin' like that happens? And everyone handles shit different, right? I don't think it's weird, bro."

"I'm just trying to look out for you, little brother. It seems a little suspicious—I don't want your compassion for this little girl to hurt you in the end." Leo said this without directly looking at Raphael, so as to spare his pride; he instead scanned the active skyline, the helicopters taking weather and traffic surveys on and off the island, the deepening, Sin City atmosphere, the sirens growing louder and less far-between.

Raphael almost told his brother he didn't need him to look out for him, but held his tongue, knowing from the last two months that it wouldn't be true. Something about taking in the little girl and playing with both her and with Mikey—something the two of them had stopped doing over the last year-and-a-half—reminded him that it felt good to be needed and looked up to, and he could, for small moments, like light between floorboards to a dark basement below, use this to see himself through Leonardo's eyes.

"She's… she's just a little kid, y'know? She shouldn't have to deal with us bein' suspicious, man—she shouldn't have to deal with any of this. She should be at home, with her mom, doin' homework and… I don't know, playin' baseball outside or somethin'. I don't wanna make anythin' harder for her. At least she's safe with us."

Leo nodded, still studying the skyline; he could feel from his brother's voice that a war was happening on his face.

"I know, Raph, and it's… well, it's noble of you, to say the least. But I guess what I'm saying is that—well, I'm afraid for you."

"Why? Aren't I doin' the right thing? I didn't know what else to do—I mean, the Foot killed her mother, and they're our enemies, right?"

Leo shook his head. "It's not that I don't think you did the right thing—I mean, I was there, I would've stopped you otherwise—it's just that I'm worried you're confusing how you feel about Splinter being gone with what's happened to this little girl. I'm worried you won't see things clearly when you need to, and you won't be able to let her go."

"What about Mikey?" Raph asked, somewhat more confrontationally.

Now Leo looked at him. "I'm not worried about him—he's far more tied to this family as a whole than you allow yourself to be openly. I've seen him give up far more so that we can stay together. It's one of his stronger points—and one of your weakest. You tend to see us each as individual elements and forget us as a unit. So you and I are going to train out here as a unit until you get it."

It happened so fast and came so far out of left field that Raphael didn't notice until he felt distinct cold on his wrist, and looked down; Leo had handcuffed them together, his left hand to Raph's right. Raphael felt like punching him.

"You gotta be kiddin' me!"

Leo smiled a bit facetiously. "Just be thankful you're handcuffed to me instead of to Mikey—at least I won't be obnoxious about it."

Raphael growled and ranted as Leo began leading him toward the edge of the wall. "You are obnoxious—every, single, know-it-all, goody-two-shoes Bushido bullshit thing you say is obnoxious! Even your face is obnoxious!"

Leo only laughed at him, serving to make him angrier. "Talk is cheap, little brother; if you can actually work in tandem with me, then I'll unlock us. Shouldn't be too hard—all you have to do is pay attention." He began running, feeling Raph's weight drag on him as he resisted.

"What are we doing?" Raph asked apprehensively; something about being chained to his brother and robbed of his independence so high above the ground was making him feel a bit queasy.

"Jumping, of course, so I suggest you start building up speed!"

Raphael barely had time to do this before they were leaping through the air to the next rooftop; he was forced to watch Leo's landing position and try to keep his even, so the shock of hitting it wouldn't jar him. He was not successful, and both landed straight on their faces. Leo looked at him, after peeling his nose off the roof painfully.

"Try again, little brother."

"Hey—if we're workin' in tandem, then that was half your fault," Raph pointed out.

The sky had dimmed from red to midnight blue, showing off the glare of Manhattan lights; sirens conquered the city—reminding Raphael of free nights, unfettered. He almost sensed in himself regret, until he felt the reminder on his wrist. This was the meaning of being a person, defined only by the presence of his brothers, without whom he was a ghost. He and Leo helped each other awkwardly to stand. They ran again, and again; the third time, jumping a shorter distance, they managed to land at the same time and absorb the shock equally. On a fourth try, however, Leonardo did not pick up speed fast enough to reach the height of Raphael's jump; when the disparity became too great at the point of the arc, Leo's weight pulled them both downward, and they missed the next roof by several feet. Raph plunged his sai into the side of the building, holding them both from falling ten stories down, and feeling as though the handcuff would rip his arm off.

"Leo—see if you can grab my arm instead of hangin' by that thing, huh?"

Leo swung upwards and they grasped by the forearms. Raph wouldn't be able to climb using his sai unless he had the use of both hands, and told his brother so; Leo, however, smiled.

"I'm borrowing your other sai; this is going to be extremely hard, Raph"—Leo said, reaching up to take the sai from his brother's belt with his free hand, and then plunging it into the wall as well—"but we're climbing this wall like a single person."

Now possessing a tight grip on the wall of his own, Leo wound their handcuffed forearms together and flexed his muscles; once he'd done that, he took the sai out and plunged it in again at the same level as Raph's significantly higher up.

Raphael watched him disbelievingly, flexing his arm as hard as possible to stop Leo from falling. "This is insane—just unlock us before we both die, ya moron!"

Leo looked at him, now that they were level. "Climb. I've got ya."

Shaking his head and trembling slightly, Raph tensed his arm muscles again to stay up, with only Leo to support him after he'd taken the sai from the wall, and dug it in higher up. He then shifted his weight to it and used it to pull them up a couple feet. He felt Leo put his weight on him, and helped him lift up to do the same, overhand, overhand, until they rolled, exhausted, over the ledge and onto the roof.

"I swear to God, Leo…" Raph said, panting. "You are one goddamn heavy turtle."

"You're no tinkerbell yourself, you know…" Leo said, sounding half-dead. "But that was really good… A few more jumps and then it's dinner time."

"Okay—but we're not eatin' like a single person. I'll take a hacksaw to these things if I have to."

"This is a most touching scene," came a foreign voice from the other side of the roof; English did not appear to be the person's first language, and this explained itself when they saw it to be a Foot ninja, perched on the far ledge. "Stand, turtles—I come to deliver a message."