"Junjō Mistake" is a romantic comedy manga that explores themes of mistaken identity, love, and personal growth. The story centers around two main characters: Rui Aiba, a high school student who is often mistaken for a girl due to his delicate appearance, and Shizuku Mizutani, a tomboyish girl who is frequently mistaken for a boy because of her short hair and athletic build. Their lives intersect when Rui, tired of being treated as feminine, decides to cut his long hair and adopt a more masculine appearance. Simultaneously, Shizuku, frustrated with being perceived as masculine, decides to grow out her hair and embrace a more traditionally feminine look.

The narrative takes a comedic turn when Rui and Shizuku meet for the first time after their respective transformations. Due to their new appearances, they initially mistake each other for the opposite gender. This misunderstanding leads to a series of humorous and awkward situations as they navigate their growing feelings for one another. As the story progresses, both characters grapple with their insecurities and societal expectations regarding gender roles and appearance. Their relationship evolves from a series of comedic misunderstandings to a deeper emotional connection, as they learn to accept themselves and each other for who they truly are.

Supporting characters, such as Rui’s childhood friend and Shizuku’s classmates, add depth to the story by providing additional perspectives on gender identity and relationships. The manga balances lighthearted humor with moments of introspection, creating a narrative that is both entertaining and thought-provoking. Through its exploration of identity and romance, "Junjō Mistake" offers a fresh take on the romantic comedy genre, blending humor with meaningful character development.