In order to protect her beloved younger brother, she became a huge breasted toilet of a wealthy man and became a masochist for 10 days.

Momoka lost her parents, dropped out of high school and raised her younger brother on her own. However, he applied without realizing that his younger brother was a part-time job, and was threatened by a group of semi-criminals. When she went to apologize with her younger brother, the leader, who fell in love with Momoka's beauty, suggests that she be given a 10-day mistress, besides her, she drinks the demand... The leader's sex is rough and sadistic, treating women as a way to treat sex... However, the slowness of the candy and whip, and the carelessness of being treated, Momoka gradually awakens as a masochist...