In a world ravaged by spatial quakes—devastating phenomena that killed over 150 million people 30 years ago—high school student Shido Itsuka encounters a mysterious girl, Tohka Yatogami, at the epicenter of one such event in Tengu City. These quakes are triggered by otherworldly beings called Spirits, whom the militaristic Anti-Spirit Team seeks to eliminate, while Shido's adoptive sister Kotori leads the secret organization Ratatoskr with a unique strategy: Shido must date and make the Spirits fall in love with him to seal their destructive powers through a kiss.
As Shido navigates dates with powerful Spirits like the shy Yoshino, rival sisters Kaguya and Yuzuru Yamai, deceptive Kurumi Tokisaki, and shape-shifting Natsumi, he builds emotional bonds amid battles and chases. Later arcs introduce complications like time-traveling Origami Tobiichi, whose obsession with Spirits leads to timeline shifts and personal redemption through her own "sealing." The series spans multiple seasons, blending harem romance, action, and escalating threats from inverse Spirit forms and inverse Spirits.