Once Dr. Trott returned from his seat in the main car with his medical kit, Judy took charge and began to investigate Ms. Frost's cabin, looking for whatever clues she could find connected to the murder.

Dr. Trott began a necropsy of Ms. Frost's body, operating in private inside the adjacent bathroom while the other two searched every crack, every crevice, for some kind of evidence, anything to prove that Judy Hopps was not a killer.

As Nick and Judy were crawling around on the floor, looking for clues, Nick kicked off a conversation to relieve the tension in the room that was so very obvious.

"Did you see Dr. Trott's male-mammal-purse?" Nick asked, winking slyly.

Judy rolled her eyes as she peered into the massive overhead racks above the seats.

"You mean his medical bag, Nick?" she asked. She was standing on top of the large bed, fiddling around with the intricate wire-mesh baggage racks, trying to dislodge a piece of metal that she thought looked suspicious.

"If," Nick replied, "by his medical bag you mean the old fake leopard-fur handbag he took from his wife—God rest her soul—that he uses to carry around his medical equipment, then, yeah, I mean his medical bag."

"You've got an awfully strange sense of humor, Nick," Judy said, abandoning her search in the overheads. That piece of metal, she found out, was a paperclip. While it could have counted as evidence, she had a feeling it wasn't related to the murder at hand.

Judging by the rather ugly Polaroid photograph of "Weird Al" Yakovic, circa 1986 it was clipped to, Judy knew for a fact that it wasn't related.

"YO!" Nick yelped from where he was crawling around underneath the desk. "I can't believe this!"

"What is it?" Judy asked, leaping from the bed in excitement, hoping for some kind of valuable clue. Maybe they'd hit pay dirt with this investigation after all.

Nick stood up... and revealed he had found a still-sealed packet of The Hunt game cards.

"These are some of the best cards in the game!" Nick commented, trying to open the packet. "I can see an Artemis Raven card inside it!"

"Nick," Judy said, a little exasperated by the distraction, "not to put pressure on you or anything again, but we do have a murder to prove I'm not responsible for."

Nick smiled apologetically. "I'm sorry, Carrots," he said. "I didn't mean to get distracted."

It was about then that Dr. Trott popped back through the door from the bathroom, several vials in his hoof.

"Well," he said, picking up off of Nick's question, "perhaps you shouldn't get too distracted, Nick. I've managed to diagnose what killed our friend in the bathroom."

He handed two of the vials to Nick and one to Judy, allowing himself to dig out a small notepad from his back pocket.

Nick was fascinated by the reddish liquid inside the vials he was holding. The liquid was translucent and yet not translucent, dark red with an odd bluish color mixed in with it. It was just barely see-through and looked similar to something out of Ant-Eater.

"Be careful," Dr. Trott cautioned, "those blood samples are quite important."

Nick gagged and almost dropped the vials.

"What did I just tell you?" Trott said, scolding Nick. "You could have broken them!"

Nick hated blood. He had hated blood since he was six years old, ever since the school bully had given him a bad scratch across the nose (accidentally, or at least, so he said). As he thought about the contents of those vials, it was all he could do not too faint like a goat over it.

Well, actually, Mabel the goat at the ZPD didn't faint over things like blood. Her spells were usually in reaction to loud noises or to jumpscares.

"You mean there's blood in these things?" Nick asked, a bit disturbed. "Like blood blood or that fake stuff that they spray all over Alfred Hitchox movie sets?"

"No," Trott explained gravely, "it's real blood. The good news is, I figured out what exactly it was that killed Ms. Frost. That's in the vial you're holding, Officer Hopps."

Judy inspected her own vial, seeing a whitish-grey powder caking the bottom of the glass like powdered sugar on a donut (Clawhauser's favorite).

"The victim, Ms. Juniper Frost," Dr. Trott began, "was killed by a poison called trimexanine, or TMX for short. It was all over the doorknob to the cabin. It's a fast-acting, silicon-based poison that was invented several years ago in the Reptropolis underworld. There have been several murder cases similar to this all throughout the state, and it's quite well-known as a poison."

"What's the poison's method of killing?" Judy asked, examining the powder and being very careful not to accidentally touch the lid of the vial.

"It is transmitted through direct contact with the skin," Dr. Trott explained. "The poison heads through the pores of the skin and makes its way to the bloodstream, which eventually leads to causing the heart to fail, and death."

"Sounds nasty," Nick commented.

"It is," Dr. Trott agreed, "but the thing is, it's not that easy to obtain this stuff, even on the black market. That's because it's a two-part compound—part silicon and part selenium fulminate."

"Could you repeat that in English, Doc?" Nick asked, cautiously setting the vials of blood down on top of the desk.

"The two halves of this compound," Dr. Trott explained, "by themselves, are inert, but when they are combined in any way, shape or form, regardless of the amount, it becomes a deadly poison."

Nick whistled through his teeth, contemplating the situation.

"So how does this help in any way?" he asked, not seeing the doctor's purpose of telling them all this.

"We know one thing," he replied. "Whoever murdered Ms. Frost had to have had access to a lot of either silicon or selenium fulmide."

"And," Judy chimed in, "whoever murdered Ms. Frost was also able to somehow reach the doorknob without leaving any paw prints or traces of DNA."

"How did you figure that out?" Nick asked.

"I checked the doorknob with some of Dr. Trott's supplies," Judy explained, "and there were no traces of any mammal ever being there."

"Since when?"

"Since a minute ago," she explained. "You really need to pay more attention."

"I need to pay more attention?" Nick asked. "Who's the one who fell asleep at the conference?"

"Nick, I thought we weren't going to talk about that?" she said through the side of her mouth, trying to hush him up.

"I'm just saying," Nick said, "that you looked awfully cute with the drool sliding out of your mouth."

"I guess it would have been nice if they gave me a..." Judy replied, stopping mid-sentence.

"...bed?" Nick finished for her. He noticed that Judy's eyes were no longer focused on him, but some point past him. Quick as a flash, she darted over to the bed behind him and reached for something on top of the mattress. When she had grasped the object on top of the bed, Judy's paw was held aloft, fingers clenched around a piece of gold paper.

"I found a ticket stub!" she announced.

"Ms. Frost must not have been very careful about where she put her ticket stubs," Dr. Trott observed.

"If I was in the hurry she was in," Nick concurred, "I'd probably lose my tickets, too."

"Really?" Judy asked.

"I once forgot where I put my fur trimmer after working the night shift at the ZPD," he responded.

"Oh, yeah," Judy said as she remembered that next morning when she saw Nick at the station. "No wonder your fur looked so bad."

"Ouch," Nick said. "My fur wasn't that bad, was it?"

Judy didn't answer as she examined the ticket stub she had found.

On the back was a piece of a much larger picture, with part of a painting of the Chordata Express emblazoned on the back of a shimmery golden ticket. The only feature to interrupt the flawless painting was a single, pencil-diameter hole in the middle of the ticket stub. Flanking either side of the hole was a name: K. P___ora, written in fluid, inky script.

"Weird," Judy commented. "This ticket's made out to a... well, I can't see what the name was."

"Maybe it's her evil twin!" Nick said all of a sudden, which drew stares from both Judy and Dr. Trott.

"What?" he said, annoyed. "It's possible! Look at Oximus Prime! He had an evil twin!"

"And," Judy asked, "just how would Judy's evil twin get on board the Chordata Express without being noticed?"

"Maybe she stuffed herself into a suitcase," Nick said, coming up with any sort of explanation at all to save face.

"I don't think so," Judy said as she pocketed the stub. "Question is, how could I find out who this stub belongs to?"

Suddenly, a voice from across the hall called through the open door.

"Excuse me?" the voice asked. "I don't want to interrupt something important, but I have a suggestion."

The voice belonged to a rather scrawny, red-and-black-furred maned wolf dressed in a puffer jacket and blue jeans. He was all disheveled and crooked-looking, and had Judy seen his type back in Zootopia, she probably would have arrested him for being drunk and disorderly. However, it didn't appear that he was drunk, and disorderliness wasn't a crime, per se. Rather, it was just an indicator of an animal's upbringing.

"If you're looking for a way to find out who all's on the train, here," the maned wolf said in a slightly nasal voice, "there's one guy who meets everyone on the train."

Nick jumped in, cutting the maned wolf off.

"Sir," Nick said, a little impatiently, "we have only..." (he quickly looked at his watch and read aloud the time) "...five-and-a-half more hours left to solve a murder case which my girlfriend here will be imprisoned for if we don't prove she's innocent, so could you please hurry up?"

The maned wolf backed off a bit.

"OK, OK," he commented. "Yeesh, I swear you've got to take anti-impatience lozenges. All of yous should ask the conductor. The conductor meets with everyone and punches their tickets at least eight times during the ride. He'd probably know the names of every animal on this here train."

Judy nodded.

"He's got a point, Nick," she affirmed, "and it's worth a shot. We've got plenty of time before Fangzahn's deadline is up."

Nick mulled that over and then announced, "I don't care what we do as long as it proves you innocent."

"Just let me grab my coat," Dr. Trott called out from where he was packing up his things.

As the good doctor exited the bathroom, he dug out a piece of fine stationery (borrowed from the desk drawers) and tacked it to the door with a spare thumbtack. He then proceeded to write with his pen in large letters "DO NOT ENTER—NECROPSY LAB; RESTRICTED ACCESS ONLY."

With a bit of a sense of energy in them (or just adrenalin from the intensity of the subject they were investigating), the three animals left Ms. Frost's cabin and set off through the Chordata Express, knowing the consequences involved if they were to fail.

* * *

As the other animals slipped away from Ms. Frost's cabin, none of them took notice of the tiny figure suspended from the cold, metal ceiling high above their heads. Sticky the gecko crawled along upside down and eventually ended up in the shadow of an open door. His yellow lizard eyes scanned the hallway of the train like a pair of golden lasers, ensuring he was alone in the hall. God forbid he be seen by a passing animal and be exposed. If someone found out he was on the train, they'd ask for personal information, and that would get messy, especially since he was part of the Black Flames, a network so vast that exposing just one root would lead to thousands of others. Not like he cared that much about his cousin's despicable gang; it was more out of fear of what might happen to him if he were exposed.

Whew. Good. There's no one here, he told himself.

While he was crawling around on the ceiling, spying on Lt. Hopps and her boyfriend, Sticky had noticed how fast the doctor figured out the kind of poison the assassin had used, and that they were investigating a thread that would most certainly be the beginning of the unraveling of the intricate spider web that was Plan 17.

And, the best part of all, it was the assassin's own blundering and sloppiness in how he pulled off the killing that would trip him up. Sticky had always hated that idiot in Travask's ranks, and, whether the fox and rabbit knew it or not, they were beginning to unravel the unique fabric of the master plan that dictated every single move of the Black Flames.

And he recognized now that the horrors he had been through to get this far had not been in vain. He had suffered through hell, but all he had lost on his way to this moment would be avenged.

But then he realized, this particular assassin would probably have recognized that he had been sloppy and would be working on any method necessary to hide the fact that he had been sloppy. That would complicate things.

Sticky mulled it over, and then a thought surfaced in his mind. Every instinct, every inkling of Black Flames training was telling him not to do what he was contemplating, but he could not deny the urge he felt in his gut.

With that, he came to a decision as to what to do to stop this particular assassin, and how he could prove to his cousin that he was more than just a flunky spy who was only good for taking orders.

It would be rather satisfying to put an end to this whole thing.

* * *

After looking from stem to stern of the Chordata Express for at least twenty minutes, Nick, Judy and Dr. Trott finally found Gerard the conductor in the club car.

The club car itself was wondrously decorated, with brass and gold trim amid a sea of splendid stained oak, and the dark blue carpet was most definitely a rug from the Orient, depicting dragons and pandas and other animals all living in harmony. Nick did notice, though, that the giant dragon looked more like it was going to eat the other animals, but it still looked good. A large, square counter with dark red paneling stood in the center of the car, with dozens of bar stools of various sizes that would allow all animals to grab a drink from the counter. A lone white tiger stood behind the bar, shaking, not stirring, martinis and preparing other refreshments for guests. Two more tables on either end of the car provided a place for other animals to sit.

It was in one of these that they found Gerard, sitting like a sentinel (as much like a sentinel as a short, dumpy raccoon could) at the rear of the train, sipping a cup of coffee and watching the world go by out the massive tempered glass windows.

"Excuse me, good sir," Nick called out, startling the raccoon, who almost spilled his coffee.

"Good grief," Gerard said, watching patiently as his coffee settled down again, "you could scare a guy half to death, man!"

He then took notice of Judy and his eyes widened.

"What's she doing here?" Gerard asked, almost jumping out of his fur.

"Before we go any further," Nick said, "I'd like to explain that we're here on an investigation to prove the innocence of my girlfriend, here. Please refrain from being paranoid. You'll just upset her more."

Gerard slowly complied with Nick's requests, sitting back down and placing his coffee up on the table. He grinned sheepishly and tried to avoid staring at Judy, like he was nervous to have a potential murderer in the room with him.

"We have a few questions to ask you, Gerard," Nick said, leaning forward on the table like a cop in an interrogation room. Nick was a cop, he reminded himself, and this counted as an interrogation room.

"Shoot," Gerard said, although he was busy trying to avoid looking at Judy.

"Carrots," Nick asked, "could you hand me that ticket stub you found?"

Judy obliged and dug the stub out of her pocket, pawing it over to Nick.

"Do you think we could find a listing for this passenger on the train anywhere?" Nick asked as Gerard gripped it in his little, fidgety raccoon hands.

Gerard looked it over and, after running the name listed through his memory banks, finally returned it to Nick.

"I have no idea who this is," Gerard explained.

"But you pass every animal on this train and punch their tickets," Nick protested. "How can you not know who this animal is?"

"Let me make something clear to you, mister," Gerard explained. "I ain't responsible for idjits who lose their ticket stubs. I punched it, sure, but I usually don't look at the name. If you really want to try and find out who this is, go and check the reservation list up near the front of the club car. Look for a small alcove, the list is in a folder in there."

Nick nodded.

"OK," he said, "thank you."

"It might not contain those reservations, though," Gerard explained. "Half the animals on this train weren't even meant to be on this train."

"What does that mean?" Judy asked, causing Gerard to subconsciously flinch.

"You didn't hear?" he asked, a little incredulous. "The other train bound back for Zootopia was delayed. Some kind of repair issues or something."

Nick and Judy vaguely recalled overhearing something regarding the fate of the other train. That was what the majority of the mammals boarding the train were doing—leaving the other train while it was repaired.

"Was a Ms. Frost among those who transferred from the other train?" Dr. Trott asked quizzically.

"Wait a second... Frost," Gerard said like a deep thinker, rubbing his chin. "Hmmm... was she a tall and lanky snow leopard with a black skirt?"

Before Nick could answer, Gerard shook his head.

"Sorry, that was Phyllis, my MuzzleBook friend from Umberland," Gerard said. "I got nothing, fox."

Nick nodded in frustration.

"Come on, guys," he said, motioning for Dr. Trott and Judy to follow him to the destination they had been given. Their interrogation with the conductor had only been partially successful, if at all. They at least knew where to find some information.

As they left, Judy caught a glimpse of Gerard fleeing the car in what appeared to be panic, getting away from a possible murderer as fast as possible.

Sure enough, inside the small alcove, in a small wall-mounted file holder, was a folded sheet of paper with dozens of columns for printing names, which had been scribbled on, apparently, by the same writer, evidenced by the single style of script used.

"This is it," Nick said, removing it from the file holder, "the passenger list."

Nick's eyes immediately began to scan the piece of paper. He quickly realized that a lot more than just the names were listed on this sheet: whoever wrote it included the species name for each and every entry.

As he made his way to the section containing all names beginning with the letter F, Nick had to blink his eyes a couple times to make sure he wasn't missing it.

"There's no listing for a Frost anywhere on the train," he announced.

"What?" Dr. Trott asked, peering over Nick's shoulder. Judy peeked up from where she stood and confirmed Nick's suspicious find: Juniper Frost was most definitely not anywhere on the registration sheet.

"That's weird," Judy commented. "Try seeing if you can find anyone listed as 'snow leopard.' It might help begin to narrow down a few suspects."

Nick obliged and began scanning. Almost immediately, he came across the only entry for 'snow leopard' on the entire sheet.

"K. Pangora," he announced, pointing out the name, "is the only snow leopard on this train."

"But why would Ms. Frost have Ms. Pangora's tickets?" Judy asked, not following the situation.

"Ever heard of an alias, Carrots?" Nick asked.

"I think my brother Devin caught one of those when he was eight," Judy said. "It was a nasty-looking thing he kept in a jar on his dresser. Scared the life out of me when I walked in his room."

Nick facepalmed.

"Carrots," he said, "I love you, but you do act like a ditz sometimes."

"Was that a compliment?" Judy asked, not quite sure how to take it. She weighed it for a few seconds, and eventually decided to believe the best. That was something Nick had always admired about her—she believed the best about animals.

"An alias," Nick explained, "is a fake name someone gives themselves if they don't want their real name to be discovered. Like how baddies in movies give themselves false identities—you know, like a secret identity, only evil instead of good."

"I suppose that's possible," Judy admitted, "but, the question is, why?"

Dr. Trott had been standing to the side contemplating Nick's discovery for the past few seconds. He then seemed to get an idea, standing up straight as he turned back to talk to the others.

"I might have an idea for you two," he explained as Nick slid the sheet of paper back into the sleeve on the wall. "I remember a little phrase my wife taught me before she passed on: 'you can tell a lot about a mammal by the contents of their luggage.'"

Nick cocked his head, unsure of how this would help their investigation.

"What I mean is," Dr. Trott explained, "you should see if you can access the baggage car and poke around in there for Ms. Pangora's luggage to find out who exactly she is, and why she might be impersonating another animal."

Nick nodded as he thought that over.

"How would we even get into the baggage car?" he asked.

"The door is in the back of the kitchen in the dining car," Trott said. "I tell you what, Nick—let's split up. I'll go throughout the rest of the train and ask a few passengers some more questions. Maybe I can find a few more clues on my own and report back to you when you return."

"And meanwhile," Nick affirmed, "we poke through glory-knows-what trying to find stuff that might not even exist."

"Nick Wilde," Dr. Trott explained, "if from what I remember of your college life is true, then you have a knack for poking through glory-knows-what."

Nick shrugged.

"You've got a point, Doc," he admitted. "What do you think, Carrots?" he asked, turning to Judy.

Judy's violet eyes were still full of worry and trepidation, even if it was partly obscured by her thoughts. All Nick could think about when he looked into her eyes was the sheer terror of what would happen if they failed in this case.

If Nick had ever doubted the ferocity with which he would fight for his Carrots, the doubts had vanished by now.

"I'm game," Judy said slowly as she checked the clock on her phone. "I just hope we have enough time—we've only got four hours and forty-five minutes left!"