Following a devastating family tragedy that leaves Tooru Honda homeless and camping in a tent, she finds solace in the Chinese zodiac tales her late mother used to tell. Unaware of the property boundaries, she inadvertently pitches her tent on land belonging to the Souma family. By chance, she encounters Shigure, an elder Souma relative, and Yuki, a popular student from her school. Initially assuming she lives in the neighborhood, they are surprised to discover the truth when they spot her returning to her tent one evening.
The Souma family extends a helping hand by inviting Tooru to live with them, significantly improving her circumstances. However, her new existence takes a bizarre turn when she stumbles upon a heated argument between Yuki and his fiery cousin, Kyou. While attempting to intervene, Tooru uncovers the Souma family's profound secret: its members transform into the animals of the Chinese zodiac when embraced by someone of the opposite sex.
Now aware of this truth, Tooru embarks on a unique and frequently comedic chapter of her life, navigating friendship, romance, and the complexities of her newfound family.