Disclaimer: see previous chapter.
(shakes head bemusedly)
Wow. I apparently have not only repeat but chronic reviewers. I'm amazed and flattered that you're following this story!
The Detective Boys had learned well from their mentor, so it was perhaps not surprising that on Monday morning they noted both Ai's absence and Conan's abstracted air and made some rapid connections before their little group had even entered the schoolyard. If Conan hadn't been preoccupied, he probably would have been able to predict the barrage of questioning that followed.
"What's wrong?"
"Is Ai sick?"
"Will she be back tomorrow?"
"Where is she?"
"I'm not sure," Conan told them, half-laughing and one hand trying vainly to smooth down the cowlick at the back of his head. "The professor only told me that she had to go away suddenly."
If he had been less nervous and distracted, he might have noticed that the Detective Boys were less than convinced.
Ayumi's eyes narrowed slightly. That didn't seem like the Conan she knew at all. In her experience, Conan never gave up on even the smallest of mysteries until they were solved to his satisfaction, sometimes without even realizing what he was doing. Whatever else happened, she was certain Conan would have gotten everything the professor knew out of him somehow.
Mitsuhiko regarded his friend dubiously for a different reason. He'd seen Conan use that same wide-eyed look and cheerful voice to grownups before. Usually just before, after, or during times when he was poking into something that he knew the grownup in question would not approve of. This did not make Mitsuhiko inclined to trust anything Conan said while using that expression or tone of voice.
Genta probably couldn't have verbalized why he didn't believe the story, but it was really quite simple. While adults might have been fooled by the act, Genta was a child himself and also knew Conan. The idea of an innocent Conan, much like that of a vegetarian sabertooth tiger, set off subliminal alarm bells.
Without any signal being given, the three lagged behind Conan slightly. A silent flurry of traded glances and gestures quickly established the mutual nature of their misgivings. A few more emphatic but still silent motions established a rapid consensus. They would not call him on the matter yet, but neither would it be dropped.
The confrontation was merely to be postponed, not forgotten.
Quickening their pace, the three followed Conan into the classroom so smoothly the distracted detective never even noticed the byplay.
Over the following week, things kept Conan distracted and prickled the Detective Boys' suspicions, such as how their lead detective began consistently leaving their company to go to Professor Agasa's and gently but firmly putting off their requests to come along.
In the lab, several milliliters of the antidote were sacrificed for research purposes. Conan carried out the tests himself, politely declining the professor's careful offers to help run the analyses, though he did gratefully accept Agasa's suggestions and help setting up and using the equipment. The professor continued to exercise admirable tact, ensuring that his former neighbor had access to the devices and materials he needed before bowing out. Perhaps he sensed Conan's need to get control over something in his life; whatever the reason, Conan was profoundly grateful in the rare times when he was not busy and could think of it.
Working from the warning in Ai's note, Conan quickly established that the compound did indeed deteriorate upon exposure to light. Within few minutes, depending on the source and intensity of the illumination, the samples of the translucent dark liquid would suddenly and completely turn clear. The change appeared permanent, and Conan tested the changed samples despite the professor's objections to the idea. Instead of burning, they had an unpleasant, almost slimy taste faintly reminiscent of soda that had gone flat, and they proved to have no apparent effect other than a mildly upset stomach.
Conan would not let Professor Agasa run tests or make any notes about the antidote itself, arguing that Ai had all the information necessary and that any investigation on their part would be not only redundant but a dangerous possible source of leakage to the Org. He had burned Ai's note and flushed the ashes down the sink and done the same to his own note to ensure that they would leave no incriminating evidence. However, he did allow the elderly scientist to run a full battery of tests on the transparent fluid that resulted from denaturing the samples, which proved to contain nothing more remarkable than a variety of common organic compounds. Agasa was still unhappy that Conan had tested the stuff on himself before the analysis, but was relieved to find nothing in the results that was likely to cause any lasting harm.
Agasa covered for Conan's visits by telling Ran that a friend had given him a junior chemistry set his own children had no interest in, and that the little boy was fascinated with working through the experiments – under Agasa's watchful eye, of course, he assured her. And so she did not worry overmuch if Conan came home with scorch marks on his sleeves, or smelling of strange chemicals. Besides, she felt it was worth it to see the triumphant light in his eyes when he returned from one of the sessions. He seemed so much more cheerful and animated that Ran thought it must be doing him good and didn't have the heart not to let him go. He seemed to enjoy it so much and looked forward to it so eagerly, and he was in such better spirits than he had been over the weekend.
On his part, Conan carefully concocted likely-sounding stories of color changes and fizzing, things that would interest a small boy enough to be recounted with bouncing excitement. He even went so far as to carefully and artistically plant stains in strategic places and brush dilute solutions of aqueous ammonia or other aromatic compounds on his clothes to lend credibility to his tales.
Meanwhile, in his actual experiments he discovered that UV light could trigger the change much more effectively, and with the professor's help devised some small devices to emit a UV flare that would convert a sample of the compound in seconds. A more powerful, remotely-triggerable version was made, waterproofed, cleaned thoroughly, and dropped into the bottle itself, a controller left in each of their possessions.
Ran was surprised when Conan took a sudden fancy to a small, clear glass perfume bottle with an eyedropper built into the cap. When queried, he gave such an adorable story about a bubble-blowing game that she let him have it and even cleaned it out thoroughly for him. A little while later, he proudly showed her a plastic ring that had been cleverly fastened to the stalk of the eyedropper for him by the professor. Ran smiled and thought fondly of the old scientist who was so accommodating for a small boy.
She was not shown the round sticker that soon afterward found its way onto the base, the oddly thickened center nestled snugly into the hollow at the bottom of the bottle so that the base appeared flat upon cursory inspection. Nor was she shown the careful, precisely engraved lines that appeared on the glass stem of the eyedropper at exactly spaced intervals. And she was not informed when the bottle unobtrusively became a constant presence in his pocket.
Conan was busy with other preparations, too. Agasa helped him move some items, but other things he could only do on his own.
Not least of these was some hard thinking and planning.
And the formulation of another note.