简要：After the massive earthquake in northeastern Japan, Mitsuo was sent to a mental hospital in deep sorrow for clearing up the ruins of the disaster. Three years later, when he was released, he felt a burst of happiness as his brother Yuta, his wife Yoko, their first daughter Chie, and their second daughter Itsuki, who had Down's syndrome, welcomed him back. The next day, Chie wanted to go to an amusement park, and Mitsuo took Chie and Itsuki there. But these happy moments won't last long, and the events take place in the park. As Sanxiong looked away from them, Chie threw Itsuki onto the concrete. Yoko couldn't accept Itsuki's death, so he frantically asked Chie and Mitsuo. Under this pressure, Chie said, "Uncle Sanxiong gave up a relationship. When Yoko collapsed due to shock, Yoko became more and more regretful day by day. He accused Yuta and questioned whether Itsuki's death had relieved him. Hearing the quarrel between his parents, Chie's heart slowly grew."...
