テセウスの船

In the aftermath of a horrific mass poisoning at a small-town elementary school in 1989, the local policeman, Sano Bunko, is arrested and sentenced to death for the crime. Fast forward to 2017, his son, Shinichiro Sano, now an adult, has never met his father but is haunted by the possibility of his innocence. Driven by a need to clear his father's name, Shinichiro begins his own investigation. Miraculously, he finds himself time-traveling back to 1989 after visiting the old school site. Now, living through the days leading up to the tragedy, Shinichiro must navigate his dual existence, gathering evidence and forming connections in the past to prevent the disaster, all while grappling with the moral and emotional complexities of altering history. (Unreviewed summary by Grok 2)