As he concludes his time in middle school, Rentarou Aijou summons the courage to confess to his beloved. Regrettably, his plea is met with rejection, marking his 100th consecutive dismissal. Encountering a trail of heartbreaks, he resorts to seeking solace at a matchmaking shrine, where he prays for the prospect of securing a girlfriend during his upcoming high school years. A surprising turn of events unfolds when the shrine's deity materializes, pledging that Rentarou will encounter a hundred soulmates throughout high school.
Initially skeptical, Rentarou eventually recognizes the validity of the god's proclamation, as two of his soulmates - Hakari Hanazono and Karane Inda - declare their affection for him on the very day they meet. Yet, an overlooked detail remains: if any of his soulmates fails to establish a relationship with him, their life will be forfeit. Amidst this life-and-death predicament, Rentarou resolves to engage romantically with all of his soulmates.
With a heart expansive enough to accommodate a multitude of relationships, Rentarou navigates his unforeseen high school journey, resulting in the burgeoning growth of the Rentarou family.