After accidentally breaking a mysterious bottle, a guild receptionist named Ryou frees a fairy who thanks him by transporting him to a parallel world. In this new reality, the standard of beauty is completely reversed; women who would be considered unattractive in his original world are viewed as gorgeous here. The gender ratio is also heavily skewed, with women vastly outnumbering men, making Ryou an object of intense romantic and physical interest simply for being male.

Ryou soon encounters the S-rank adventurer party Rosenkreuzer, a group of powerful and capable women who are, by this world's standards, considered unlucky in love and past their prime for marriage. The party members, who in Ryou's original world would be seen as stunning beauties, are instead regarded as unfortunate-looking spinsters in this reversed society. Ryou finds himself relentlessly pursued by these women, leading to a series of erotic encounters as he navigates his new harem situation.

The story progresses through Ryou's experiences in the city of Cassandra, where the Rosenkreuzer party has its base. The narrative expands beyond the initial harem as Ryou attracts the attention of other groups, including a Dark Elf and assassins from the Dark Guild. An arc involves Ryou being captured by the Dark Guild, only to be unexpectedly installed as their new guild master, forcing him to juggle his duties to the guild's female members while searching for a way to escape his predicament. The original Ryou from the reversed world is implied to have been transported to the protagonist's original world, where he enjoys similar romantic success with women who are considered unattractive there but would be beautiful to him. The manga concludes after four volumes, following the publication of the final chapter in July 2025.