In postwar Japan, a traumatized former fighter pilot joins the civilian effort to fight off a massive nuclear-enhanced monster attacking their shores.

Kaoruko and Kazumasa Harima are a separated couple with two children. They plan to divorce once their daughter, Mizuho, enters elementary school. One day, they receive devastating news of their daughter falling into a coma after a near-drowning accident at a pool. The doctors declare her brain dead with no prospect of recovery and the couple must decide if they should donate her organs to others in need or to wait until her heart stops beating.