Chinatsu and his older brother, Fuyuki, have been trained by their father to become professional assassins for their whole lives. However, Fuyuki is slain as a result of Chinatsu failing at his first job. Chinatsu is discovered by a blind boy who lends him a shoulder to cry on. The trauma still haunts Chinatsu five years later, and he is unable to kill any of his targets as a result. While waiting around the streets, he recovers a stolen object owned by Kasumi, the blind boy he had met back then. As a token of gratitude, Kasumi invites the assassin to his home that is located in a traditional Japanese inn. Chinatsu learns that the boy sees himself as a burden to his family due to his disability. Despite being complete strangers, Kasumi feels a connection with Chinatsu and asks him to be