Hana, a stunning university student who spends most of her days working part-time jobs, travels to Yuigahama with a friend for a bodyboarding trip and reunites with Kaito, her first love whom she has not seen in ten years. Kaito has become a surfer and still carries the gentle demeanor Hana remembers from childhood. The two quickly rekindle their feelings and fall into a seemingly perfect romance. However, Hana soon discovers that Kaito harbors a deep and disturbing secret. When she kisses him for the first time, his personality abruptly shifts into someone violent and unrecognizable. This second personality belongs to Aoba, a man from Hana's past who once tormented and violated her. The explanation is tied to a heart transplant: Aoba died in a traffic accident, and his heart was donated to Kaito. The transplant caused Aoba's consciousness to persist within Kaito's body, and the two personalities switch places every time Hana and Kaito kiss. Aoba holds Hana hostage by threatening Kaito's body, forcing her to submit to his advances in order to protect the man she loves. The one-sided power dynamics become more complicated as Hana begins to understand that Aoba, despite his cruel actions toward her, genuinely loved her in his own twisted way and that she also developed hidden feelings for him. Kaito, once he becomes aware of his condition and the relationship between Hana and Aoba, struggles with jealousy and helplessness but ultimately encourages Hana to confront her feelings for both men. The story reaches its climax when a traffic accident puts Hana in danger, and it is Aoba who sacrifices himself to save her, an act that forces a resolution among the three. In the end, both personalities manage to coexist within Kaito's body, and Hana accepts her bond with both Kaito and the lingering presence of Aoba. The narrative explores themes of identity, trauma, possession, and the blurred lines between hatred and love, framed as a suspenseful love triangle contained within a single body. The setting shifts between the coastal town of Yuigahama and urban locations, with the beach serving as the symbolic site of reunion and emotional turning points.