Childhood friends Matsuri Kazamaki and Suzu Kanade possess the unique ability to see ayakashi, mystical beings seeking life force. Their bond weakens in high school as Suzu's feelings deepen, mirroring their differing views on ayakashi: Matsuri sees them as threats, while Suzu, an ayakashi medium, embraces them despite the danger. Encountering a talking white cat, Shirogane, reveals a sinister truth—he is the ancient 'King of Ayakashi' aiming to devour Suzu to amplify his power. In a desperate move to protect her, Matsuri intervenes but ends up transformed into a girl by Shirogane's magic. Vowing to shield Suzu as her female best friend, Matsuri seeks a reversal from his ninja grandfather. Amidst this chaos, Suzu grapples with her evolving romantic feelings. As Matsuri forms an uneasy alliance with the king, their intertwined destinies hang in uncertainty.