The story is about Takanashi Momoko, a 16 year old girl. Her life is pretty normal, until her twin brother, Akira, disappears. Akira was supposed to enter a high class all boys school but he runs away to pursue his dream of becoming a photographer, leaving only a note explaining his actions. At first Momoko and her mother thought it was just a joke but he really didn't come back. Now Momoko's mother went ballistic and started cutting her daughters hair saying that she has to take her brother's place until he comes back. Not good for her since she has to disguise herself as a boy and what's this about being roommates with another guy? Will she be able to hide her secret and survive or will she be found out?
- Momoko Takanashi
- The main female lead, who has to attend (an all boys) college in place of her twin brother due to him running away from school.
- Itou Kunio
- Momoko's roommate. He first meets Momoko when he saves her (while she was a girl) from getting hit by a car. He calls her stupid for not paying attention and she returns that he is a bastard. After discovering that she is a girl, he tries his best to protect her identity.
- Akira Takanashi
- Momoko's twin brother. He runs away leaving only his school uniform in the closet. When Akira later returns, he admits he ran away to be a photographer.
- Principal's son. He knows that Momoko is just disguising herself as a boy. He tries to black mail Momoko into going out with him. Though later he becomes good friends with Momoko.
- He is gay and likes Itou. He tries to use Momoko to bring him closer to Itou. He thinks that Momoko is actually a boy and that him and Itou are both gay and dating.
- Momoko's first love and childhood best friend. Momoko and Itou meet Ryou during vacation when the couple wanted to spend time alone with each other. Turns out, when Momoko and Ryou were children Ryou gave Momoko a bouquet as a promise that they'll be together forever...