The Ship of Theseus

Shin Tamura works as a relief teacher at Otousu Elementary School at Satsuki Kimura's arrangement. He also decides to prevent the incident in the village that led to his father's arrest. According to Yuki's notes on the incident, Yoshio Tanaka's home will catch fire in three days. While investigating the Tanaka family, Shin finds a note with a drawing of two creepy girls and thinks they are somehow related to the incident at Otousu Elementary School. Shin's sister Suzu goes missing, throwing the village into disarray. This unexpected development upsets Shin, and a rift forms in his relationship with Bungo.

Shin Tamura is accused of a series of incidents in Otousu village and is arrested by detective Shigeo Kanamaru. Shin manages to discard his notebook detailing future events the moment before his arrest. It is imperative no one learns that Shin's father, Bungo, will commit murder. However, the driver's license that should have been thrown out with the notebook arrives when Shin is released. Whoever is responsible must have picked up the notebook! The true criminal antagonizes Shin further by foretelling a future crime with another strange drawing. What is the next target? Kazuko is concerned for Shin, who is struggling to save his family by revealing the unfortunate potential future.

Shin returns to the present day, where a changed past awaits him. His father remains imprisoned under false accusations, his mother and brother committed suicide, and his sister is missing. Shin feels deep regret for changing history for the worst. Shin visits the family home of his beloved wife Yuki with the faint hope of encountering her. Next, Shin visits Bungo in the detention center and vows to clear his name of the false accusations. He then goes to see his estranged sister, who changed her name to Ai Murata and lives in hiding. Shin asks her to help clear Bungo's name, but she refuses to let him disrupt the life she shares with her husband. Feeling despondent, Shin comes up with a reckless plan to rescue his father. However, he is met with harsh difficulties.