Kirishima Shirou (age 24) was suddenly downsized from work and his girlfriend dumped him. When he was complaining to his friend at a bar, a mysterious, beautiful, big breasted woman named Ishimura Ai asks him if he would like to work for her!
While drunk he ends up signing a contract with her. But the next day he goes to her place, and she walks out naked! He found out the truth about the contract. It wasn't a work contract but a marriage registration form.