As a talented young man, Minamoto Hitomihiko was kidnapped by the men in black and brought to the organization, and became the organization's number one killer. Later, he was discovered by Gin because he secretly contacted the FBI. He drank APTX4869 and turned into a child. After reuniting with his childhood sweetheart and lover Huihara Ai, he was involved in one strange case after another. Finally, he and Conan and others defeated the black organization.