Mikazuki Mao Can't Choose a Gender

"I hate men!" Mao was harshly dumped by her boyfriend. She fell asleep while feeling totally dejected... and turned into a man the next day! Not knowing how to turn back, it was decided that Mao has to live in a dorm as a guy. However, her roommate, Ryuusei, is extremely curt and annoying. How will her life turn out?!