For ordinary individuals, being stabbed to death would represent the end of their journey. However, for Rin Asogi, it is merely an inconvenience. Rin possesses immortality, which proves beneficial when she frequently encounters dangerous situations as a private detective.
Rin has consumed a "time fruit," a fruit from the guardian tree Yggdrasil, which renders her incapable of dying. Despite this, others continue to attempt to kill her, and throughout her long existence, Rin has experienced various violent deaths, including being shot at, cut up, maimed, tortured, and countless other forms of violence.
However, the year 1990 marks a turning point in Rin's life as she finds herself facing an imminent threat to her survival. Someone is hunting down immortal women like Rin, putting her life at risk. Over the course of 65 years, Rin has witnessed those around her age while remaining unchanged herself. Higher powers are pursuing her, and Rin must employ all available resources to protect herself from certain death.
Rin's journey begins when she searches for a lost cat but discovers an amnesiac named Koki Maeno instead.