Murderer, Shinichi Kudo Heiji takes Kazuha, Kogoro, Ran, and Conan to East Okuho after receiving a letter from Makato Okuda addressed to Shinichi; The letter tells Shinichi to meet with him so he could explain Shinichi's deduction mistake from his past investigation. Upon arrival, the group learns that Makato has been missing for over a year; Conan separates from the group and heads to the meeting location disclosed in the letter and is subsequently trapped inside a shed by an unknown culprit. Conan realizes that he mistakenly took the antidote to the APTX 4869 in place of his cold medicine; He escapes through a window and falls into the river before becoming Shinichi again. Heiji and the others find an amnesic Shinichi by a shore; the villagers believe that the Shiragami, a deity living in the forest, cursed Shinichi resulting in his amnesia...