Dressed in a cute uniform with a blazer and pleated skirt, and completed with a hairband to complement her long wavy hair, Noeru Minamino arrives at Morinomiya Boarding School―albeit a month late. However, Maria Minamino, Noeru's twin sister who was accepted prior, is devastated to see this, as Noeru is actually a boy! Due to certain circumstances, he is only able to enroll as a girl.

Noeru's decision to join Maria stems from Maria's interest in the school's basketball coach. As her inseparable twin, he finds this hard to accept and hopes to bring her back home. However, a wrench is thrown into his plans when he starts falling for his mysterious roommate, Miyu Makimura. Matters become even more complicated when he finds himself being courted by the ace of the school's basketball team!