Detective Conan OVA 10 - Kid in Trap Island

Conan Edogawa is sick and has to stay home with a cold. He overhears Sonoko Suzuki telling Ran Mouri to dump Shinichi Kudo and instead date Dr. Tomoaki Araide. Conan gets angry over this, and falls asleep, waking up to a phone call from Ai Haibara. She tells him that she has created an antidote for him to try out, for testing purposes. Conan takes the antidote, and passes out. When he wakes up, he is Shinichi Kudo again! However, Haibara is gone, and everything looks strange.

It was a time of chaos, warriors from across Japan fought endlessly for the right to rule the country.

Four glowing orbs of different color fly through space, chasing after a dark red orb. After a fierce battle, only the blue orb falls to earth, into the room where Michiru is sleeping. But the dark red orb also appears on earth. The orb changes shape into the form of a boy, and starts to illegally raise Mejiro birds. Later, Michiru is at a flea market in a park, when a large flock of Mejiro birds cover the sky, and start attacking people. The yellow, silver, and purple orbs show up and almost manage to calm down the Mejiro, but violence is about to break out again. At that moment, Michiru hears a voice inside her head asking her to save the Mejiro.

In late 16th century, the era of civil war that tore Japan over two centuries is nearing its end and the regional warlords who survived the bloodsheds are ready for a final showdown. In the battlefield where your best ally turns out to be your worst enemy, only the shrewdest can come out alive.