The story follows a girl named Claudine who grows up believing that she is really a boy and will return to being a boy in the future. Her worried mother takes her to see a doctor, who in fact finds nothing wrong with the young Claudine. The two become friends and the doctor narrates the story of Claudine's roller coaster life as she falls for several women and we learn a dark secret about Claudine's father.
Claudine first fell in love with her servant girl, Maura. Maura loved her back, but was sent back to her home once Claudine told her parents that she wanted to marry her. Claudine then fell in love with Cecilia, but Cecilia was straight and secretly having an affair with Claudine's father, Auguste. Louis, Cecilia's brother, found out about their affair and killed Cecilia and Auguste out of jealousy because he'd once been Auguste's lover. It is revealed that the adult Auguste had fallen in love with Louis when Louis was just a boy. Claudine had seen the two of them together when she was 8. After Cecilia died, Claudine went to college and fell in love with Sirene. The two got together before Sirene fell in love with and became engaged to Claudine's brother, causing Claudine to commit suicide and free herself from her body because she felt it was the one thing which prevented her from becoming a "perfect man".
- We first meet Claudine when she's ten-years-old and when her mother takes her to see a doctor. She's described as beautiful, captivating and exceptionally intelligent. We learn that ever since the age of 8, Claudine has believed herself to be really a boy. Even though this worries her mother, her father has no problems with this as she takes after him and her brothers take after their mother. During her short lifetime, she got into many relationship with other girls but all have sad ends. At the end of the manga, after being betrayed by Sirene, Claudine committed suicide by a gunshot.
- Claudine is the youngest sibling of four children. Her family consists of three older bothers, her mother and her father.
- Claudine's Mother
- Not much is known about Claudine's mother save for that she is Claudine's mother, she takes Claudine to see the doctor in the beginning of the story and her three sons take after her. She rarely shows up in the storyline and seems to adjust to the idea of her daughter being a man, save for the time when she finds Claudine in a romantic embrace with another girl.
- The Doctor
- We never learn his name but the doctor is the one who narrates Claudine's life as he looks back on her case later on in his life. He shows up several times in the story; once in the beginning, again when Claudine is 15, a phone conversation when Claudine is an adult and again at the end of the story when he's possibly retired from being a doctor. Since the beginning, he becomes friends with Claudine and this helps her to talk easily with him. At the end, the Doctor shares his thoughts that Claudine is indeed a transsexual with the audience.
- Auguste De Montesse
- Claudine's father whom she takes after and cares for. He is a member of a wealthy family and took over the running of a large plantation from his grandfather. A frank and diligent person with many interests. Pleased that Claudine takes after him, he raises her like she were his son and the two spent many hours hunting, horseback riding and sitting in his book filled study talking of other lands.
- Andrew, Edward and Thomas
- Claudine's older brothers who take after their mother. They deeply love their clever sister and support her being a man.
- A beautiful girl from Claudine's childhood, she's been infatuated with Claudine since they were children and felt in love with Claudine at a young age. She finally confessed her feelings but Claudine didn't return them. However, she kept loving Claudine till the very end. Of all the girls Claudine ever met, Rosemarie is the only one that understands her true nature, stating she's "a true man given a female body". Rosemarie tends to "get in the way" of Claudine's various love interests. She got burn scars on her face in the fire caused by Louis. After that, she went to Paris and operated a shop. Rosemarie remained single and kept her love to Claudine. In the last pages, she's shown visiting Claudine's grave.
- Simoune, Marabelle, Angelique
- Friends of Rosemarie's, we briefly meet them at Rosemarie's party
- Louis Laques
- Rosemarie's tutor, we first meet him at Rosemarie's party. When he first meets the teenage Claudine, he is completely fooled into thinking that she is a he and comments on her begging Rosemarie's boyfriend. This remark makes Claudine flee the party, leaving Louis confused. When he learns who she really is and realizes who her father is, Louis races out to catch up with her but loses Claudine as she mounts her horse and races off. We meet Louis again later on in the story as Claudine falls in love with his sister. In his jealous rage, he burnt down the cabin killing both his sister and Claudine's father. He was never seen again since then.
- A young girl who comes to work with Claudine's family and Claudine falls in love with. When Rosemarie realizes this, she causes the girl to lose her way to the post office to send away her first paycheck only to lose it at one point. Maura returns home later on when she learns about the death of her father.
- Maura's mother, whom we never meet
- Cecilia Laques
- Claudine's 2nd love interest and a librarian working in a high school library. The sister of Louis, the two shared a common love in books and Cecilia started a conversation with Claudine. Since then, Claudine perused her with a passion only to find that she didn't feel the same for her. It is during this relationship that we learn of Auguste's dark secret. She died in the fire caused by her brother Louis.
- A black haired beauty whom Claudine first meets after wandering around Paris after a second meeting with the doctor by simply looking in a window of a ballet studio.
- They meet again when Claudine has entered college and the two are introduced at a party. Claudine falls completely for Sirene and the two even live together for a brief time. Yet as much as Claudine loves her, Sirene ends up falling in love with one of Claudine's brothers. The doctor is quoted in saying "no man could love a woman as deeply as Claudine did."