Haru, a human believed killed in a plane explosion, leaves his partner Kurumi emotionally shattered. A humanoid robot assumes Haru’s appearance and identity to help Kurumi recover, operating under directives while unaware of the accident’s true nature. This robot references messages Kurumi inscribed on a Rubik’s cube—personal wishes and unresolved conflicts revealing past violence where Haru physically harmed her during arguments.

The narrative later unveils that Kurumi actually died in the explosion, not Haru. The perceived robot is Haru himself, surviving with severe trauma-induced amnesia that deludes him into believing he is a machine. Fragmented memories resurface during a confrontation, exposing Haru’s suppressed guilt over Kurumi’s death and their final pre-flight altercation, where a physical fight led her to board the doomed plane.

Haru’s psychological journey involves reconciling with this truth and processing remorse. He interacts with Kurumi’s grandfather, who urges acceptance of loss through memory’s enduring presence. Alone, Haru rebuilds his life, symbolically communicating with Kurumi’s memory—such as acknowledging a self-prepared meal. Kurumi’s posthumous message on the Rubik’s cube delivers their story’s emotional conclusion.