In a girls’ dormitory, close roommates Mizuki and Ena lead a quiet life—until a mischievous prank from Ena turns everything upside down. Mizuki, the senior, finds herself drawn into Ena’s teasing games, revealing her hidden submissive nature. From that moment on, their after-school hours become a secret ritual of reversed roles and lesbian pleasure, with Mizuki surrendering both body and heart to Ena’s dominance. A hidden master-servant bond that becomes the shape of their youth.