Miri Wakana's romantic rejection by classmate Takashi Wase on their final high school Christmas drove her to desperately cling to an old diary. This act unexpectedly hurled her six months into the past, granting her the ability to leap repeatedly through time. Driven to alter future outcomes and uncover why Takashi rejected her, Miri actively manipulates past relationships and events across multiple leaps. The cyclical nature of her time travel forces recurring confrontations and revised interactions with Takashi and classmates like Miyako Anami and Ren Ashiya. Her ongoing efforts involve experimenting with different approaches during each leap to influence Takashi's feelings and decisions, aiming to prevent her heartbreak.