Left by his wife and drowning in alcohol, the only one remaining by the man's side was his lovely daughter, Yume. Worried about her father, one day Yume witnesses him masturbating. Feeling that he must be lonely, she decides to help him, hoping to bring him some comfort. She begins assisting him with his masturbation, and as a result, their relationship rapidly deepens. Drawn irresistibly to each other, they soon cross the line into an irreversible incestuous bond.