In Japan's only city where harem marriage is legal, Koharu just signed up to be wife number three to local pervert and low-key sadist, Ryunosuke Date. One night, unable to stand the cries of passion coming from her next-door neighbors, Koharu bursts out of the house and encounters wife number two, Madoka. The two are having a passionate exchange of their own when Ryunosuke steps in, declaring that one of them deserves to be punished! With a pervy husband and two bullying sister-wives to live with, will Koharu ever find marital bliss?!