Ryo Tachibana served as a yakuza underling and the trusted right-hand man to Kentaro Yamamoto in the Inugane-gumi gang. After a significant failure, their boss Kimanjiro Inugane presented them with an ultimatum: undergo sex reassignment surgery to become female idols, or choose death and organ harvesting. Opting to live, Ryo was sent to Thailand for the procedure and intensive training, eventually debuting as Mari Tachibana, the "cool" member of the idol group Gokudols.

In his former life, Ryo was a dedicated admirer of the actor Hitoshi Takamura, collecting his films and holding him in high regard. He also possessed a strong dislike for sweets, a trait severe enough to end a past romantic relationship. Following the transformation, Mari retained many masculine mannerisms and a yakuza spirit, which frequently clashed with the idol persona. A recurring physical issue from the surgery and training was chronic hemorrhoids and other anal afflictions, which became a source of distress and occasional public embarrassment.

Mari's background includes a father who is also transgender. Their relationship involved a prior family conflict that required a long period for paternal acknowledgment and acceptance after Ryo's own transition. In their new life, Mari received a considerable amount of fan mail, which sometimes provoked jealousy from other group members.

The live-action adaptation further explores these experiences, including a story arc where Mari develops a romantic relationship with a lesbian nurse who treats the surgery-resultant hemorrhoids. Another narrative moment features a television appearance where Mari was compelled to eat cake, resulting in vomiting afterward and highlighting the enduring aversion to sweets.