Disclaimer: don't own anything except the plot.

I blame this on Becky Tailweaver, whose 'Relative Truth' both introduced me to Detective Conan and seems to have gotten my interest compass stuck on it. Although Icka M. Chif and Ysabet are also probably partially responsible for the latter.

Conan was the one who found the note. The professor had been out, which was probably why the timing had been chosen.

It sat on the counter in the empty lab, a single large brown glass bottle beside it. All the rest of the equipment, glassware and chemicals, were neatly cleaned and put away; the computer, when turned on, proved to have been cleared of any incriminating files.

The note was short.

"I will be gone for some time. Do not try to contact me.

The bottle contains a new temporary cure. I believe this is the only safe way.

10 mL ≈ one hour. The formula is more stable than the capsules. It breaks down when exposed to light, so keep your supply in the tinted bottle.

You must not ever let an intact sample of this chemical fall into Their hands."

The last sentence was on its own line. The words were darker, as though the writer had pressed down hard in an attempt to emphasize their importance, and underlined twice. It was signed simply, "Be careful. -Ai."

When Professor Agasa returned, he found Conan sitting by the counter, the note in one hand but his stare somewhere far beyond it. The boy's other hand unconsciously twirled the plastic cup that sat upside down like a hat over the cap of the glass bottle, a small graduated container like those that came with some cough syrup bottles. Conan's head came up at the professor's entrance, though his stare did not move and it wasn't certain whether he even really registered Agasa's presence.

"It's a one liter bottle," the small detective said quietly. "About four days."

It was a Friday afternoon.

"I should test it first. Just in case."

The professor agreed with Conan's desire for caution, and so it was that Conan steeled himself to wait until the next day and an excuse to Ran about a new video game Agasa had found before returning to the lab.

All that evening and the next morning, he was mildly surprised to find that the lingering shock actually helped him endure the wait, deadening the nervous anticipation he was sure to have felt. Ran agreed to the proposed trip quickly, perhaps noticing her small charge's unusually subdued manner.

The trip to Professor Agasa's house went by in a blur. It was fortunate that he did not encounter any of the Detective Boys; he would not have been up to evading them.

Agasa had already prepared a room by the time Conan arrived. A brief change of clothes, and all that remained was the actual taking of the cure. Tactfully, the professor merely made certain Conan knew the room that had prepared and walked him to the lab door, withdrawing to give him some privacy.

The bottle was still on the counter, exactly where he – and Ai – had left it. Conan took a deep, shaky breath and, with hands that had miraculously stopped shaking, removed the plastic cup and the cap.

A test…he mused silently. Ten milliliters for an hour. One for about five or six minutes. That should be enough time to check for any problems.

The stuff inside the bottle had none of the viscosity of cough syrup, and he easily poured out one milliliter, a stray drop sliding cleanly down the smooth plastic and joining the rest of the murky, strong-smelling liquid at precisely the first mark. He carefully replaced the cap on the bottle and regarded the brown solution in the cup for a moment before raising it in an ironic salute, a toast to hope, and tossing it back.

The stuff tasted horrible, as strong as it smelled, and it burned, like alcohol or capsaicin or iodine on a scrape. It seared the inside of his mouth and down the back of his throat when he swallowed. He managed to drop the plastic cap on the counter, tinny hollow clunk telling him it had connected. Eyes watering, he staggered out of the laboratory and toward the room. He barely made it to the prepared place before the burning in his throat spread to the rest of him and he collapsed, the familiar agony of the change coursing through the marrow of his bones.

Shinichi Kudo woke to an unfamiliar room. He found himself lying face down and tried to get up, only to reel with a wobbly, dizzy weakness throughout his body. He tried again, more slowly, and managed to roll over. From a half-reclining position, partly on his back, partly on his side, he got his first real look at his surroundings.

He was lying on a blanket on the floor, wearing a plain t-shirt and boxers. A set of clothes lay neatly folded on the floor near his head. The room was very small, and there were angular marks on the floor, as though boxes had been there for a while and recently moved. There were no windows; the walls were a plain white, and there was a single door at one end.

Shinichi frowned and tried to suppress a rising sense of unease. Where was he? What had happened to him? The last thing he remembered was…he couldn't seem to remember for a moment, coming up with nothing with dark fog. Then he got an image, and his head seemed to clear a little. That's right, he took Ran to Tropical Land. Then there was that murder, the beheading, on that roller coaster they rode, and then…he went to go follow those two men, that was it. He remembered seeing one of them making a deal…he must have lost track of the other one…and then something hit him on the head, a vague memory of pain, and then nothing. Until waking up here, wherever here was.

The detective immediately leapt to the conclusion that he had been knocked out by his attackers, possibly drugged, by the way he felt, and brought here. He lurched to his feet, swaying slightly and leaning on the nearest wall for support. He made a desperate stumble for the door, falling back in unsurprised despair when he found it locked, when his detective's eye caught something that stopped his entire train of thought in its tracks.

The door was locked from the inside.

Shinichi slowly sank back onto the blanket, mind whirling. Wherever he was, the pieces weren't quite fitting together. A quick glance told him that there was no way anyone else was in the bare room. He was of course familiar with locked-room scenarios, but it didn't make sense to go to the trouble if the person inside wasn't dead. Was he supposed to be? Or was someone trying to mess with his head? The real test would come when he tried whether the door was locked from the outside as well, but common sense told him he should probably get dressed before attempting it.

He mechanically put on the clothes in the pile, not entirely surprised that they fit him perfectly. In the process he noticed the second strange thing since waking, not counting the situation itself. He was wearing a watch that he had never seen before, one with a strange marking on the casing. He stared at it for a moment before deciding that he had better not touch it until he had a better idea what he was doing and finished dressing.

The door opened easily once he unlocked it, and he stepped out into a hallway. There was a moment of dizzying familiarity and uncertainty, and he took a few steps out before recognizing Professor Agasa's house. He turned back to the room he had awakened in and on inspecting it in light of this new revelation recognized it as a storage room, the boxes that had been there since time immemorial unaccountably cleared out. He was about to go out again when a stab of pain lanced through him, then another. He stumbled back, into the room, and fell onto the blanket, the door swinging shut behind him as he lost himself to agony.

When the pain subsided, he regained consciousness in a child's body and knew himself again, both as Shinichi Kudo and as the masquerade of Edogawa Conan that he had been maintaining since that night.

Then the memories of the past few minutes came back to him and he groaned and began to swear under his breath as he detangled himself from his larger clothes and went in search of the ones that fit him as he was now.

Professor Agasa had a strong sense of déjà vu when he looked into the lab and found Conan again seated by the counter, staring at the glass bottle. Hearing him approach, the small detective looked up at him with a morose expression.

"Professor? I think we have a problem."