After the Japanese kidnap two Korean teenagers and take them to a comfort station to join other girls who are serving as sex slaves, only one of them survives. Decades later, the elderly woman tries to reunite with her friend's spirit.
Based on a play by Hisashi Inoue, it focuses on the sufferings of the survivors of Hiroshima. The film takes place during 4 days in the summer of 1948, as the ghost of her father visits Mitsué (Rié Miyama). He had somehow learned that she has fallen in love, and tries to convince her to start her new life. But Mitsué obstinately refuses his warm and humorous encouragements : « People were killed in my place. I do not have the right to find happiness », she says.
Satou Ichirou once called himself 'Maryuuin Kouga' and behaved as if he were a hero in a fantasy world. His strange behavior caused his classmates to bully him and he left the school. At his new school, he tries to behave like a normal boy, but one day he meets a girl who cosplays with a blue cape. She calls herself "a researcher traveling from the outer world to search for the 'Dragon Terminal'". At first, Ichirou rejects the girl, Satou Ryouko, because her behavior reminds him of his embarrassing past, but he changes his mind after seeing her getting bullied. In order to bring Ryouko back to real life, Ichirou accepts her and his past and begins the final battle as Maryuuin Kouga.