Tokyo, 1936. Kudou Sousuke is a pianist who usually plays at a jazz bar, "CADENZA." One night, he gets involved in a peculiar case: a frenzied geisha suddenly attacks him on his way home. Despite getting wounded, Sousuke overcomes the crisis and leaves the scene.
When Sousuke goes to work the next day, he learns that the geisha has been murdered and that he is being wanted for the crime. Sousuke loses his job after the master of the bar tells him that he can no longer employ a murderer.
Sousuke is now being pursued for a crime he has no knowledge of, and he is unable to return home, where his younger sister, Yuzuha, awaits him. After wandering around aimlessly, he eventually meets a stunning yet arrogant girl with shady connections who offers him temporary protection in exchange for performing various dirty jobs for her.
A few days later, he saves a girl from a gang of thugs. He finds out that she's Ayane, the girl who led Sousuke away from the military police on the night when that woman struck him. She promises him that she will look into the mystery surrounding what happened that day in order to prove his innocence.