The choir club president, Oka Satomi, is suddenly approached by the yakuza Narita Kyouji.
"Let's go karaoke!"
In Narita's group, there is an annual karaoke competition, and the boss gives the one who is the worst singer an awkward tattoo.
Asked by Kyouji to coach his singing, Satomi reluctantly goes along with the practice.
Where will this strange relationship connected by karaoke lead!?