Atsushi Ikeda, a kindhearted college student, tends abandoned animals and brings them inside his home. When he spots an injured high school student with a violin lying at his doorstep, he does not think twice about taking him in for the night. The fierce young man, introducing himself as Riya Narukawa, has no idea why he was unconscious in front of Atsushi's door but worries no further, as he claims that memory lapses are a common occurrence. The following day, when Riya gets a sudden headache while playing the violin for Atsushi, he professes that he ran away from home because his dead brother's spirit inside him has been forcing him to play the violin. Stunned by the sudden revelation, a concerned Atsushi discovers that Riya is a prodigious violinist and the only son of a famous musician. Worried that things are not matching up, he soon learns that Riya has a multiple personality disorder, causing him to invent a deceased younger brother whom he believes to be within his soul. Carrying the weight of other people's expectations for his talent, Riya tries to come to terms with the underlying problems behind his psychological complications, all while understanding what Atsushi means to him. [Written by MAL Rewrite]