In July 2016, a stabbing rampage left 19 people dead at a care home for the disabled in the Japanese city of Sagamihara. The attacker claimed that disabled people only bring misery. His words shook NHK director Yuya Sakagawa to the core. Yuya’s younger sister Ayumi has cerebral palsy and intellectual disabilities and can barely speak. Yuya lived in the same family home for over 20 years but never felt unhappy because of Ayumi’s disabilities. He wants to disprove the Sagamihara attacker’s claim but is conscious that the burden of caring for Ayumi has always fallen on their parents. So Yuya returns home, becomes Ayumi’s carer for a month, and films the whole experience. The Sagamihara attacker’s words were deplorable but were echoed widely on the web. Yuya’s self-documentary is his effort to refute the attacker’s claim. Although Yuya acted out of a strong sense of justice, he realized he had not understood his family. By taking care of Ayumi every day, he grasps their parents’ emotions and the complex feelings of his other sister Yukari. The film follows Yuya as he struggles to forge a new relationship with Ayumi and other members of the family.