Meitantei Conan: Haibara Ai Monogatari - Kurogane no Mystery Train

Before she became Ai Haibara, Shiho Miyano lived under the Black Organization as the scientist Sherry, continuing research tied to the drug APTX 4869. The murder of her older sister Akemi pushes Shiho to rebel, swallow the drug herself, and escape after her body unexpectedly shrinks. Under a new identity, she eventually finds an ally in Conan Edogawa, another victim of the same poison.

Her past catches up with her aboard the Bell Tree Express, where a staged mystery game turns into a real locked-room murder while members of the Black Organization close in. Gin believes Sherry is on the train, and Vermouth and Bourbon set their own plans in motion. Trapped among suspects and enemies, Haibara must survive a journey designed to expose the identity she has fought so hard to leave behind.