Akira returns to his hometown and reunites with his childhood friend Itsuki, only to discover that her twin sister, Sayo, has been in a coma for six years. After sharing a final, passionate night with Akira, Itsuki reveals her hidden resentment toward her sister and makes a supernatural pact with a mysterious girl named Chinatsu. Itsuki sacrifices her own life to wake Sayo from her coma, but the miracle leaves Sayo with total amnesia, forgetting her own name and identity.