Waking up in an unfamiliar bedroom within a dream world, teenager Haruto Tsukishiro discovers a peculiar app on his phone. Upon activating the program, a strange woman appears and attempts to drag him into her realm. Fortunately, a mysterious white-haired girl severs their connection and assists him in escaping, revealing that the woman is a witch; however, their conversation is abruptly cut short. As Haruto re-enters the realm, he encounters Katsumi Kanzaki, an anthropomorphic talking cat. While the witch's minions pursue them, the white-haired girl opens a door to allow them to escape. Following their ordeal, Haruto describes their savior—who is visible only to him—and Katsumi, the leading authority on dream world research, realizes she must be "Lily," a being that resurfaces repeatedly across multiple dreamscapes. Hoping to exit the dream world through a blue door, they enter the witch's realm once again. Finding themselves in peril, Lily reveals the truth to Haruto: witches suffer from "Sleeping Beauty Syndrome," a coma-like sleep state induced by torment in their real-world lives. Consequently, they cannot wake until they are defeated in the dream world. After finally defeating the witch and locating the blue door, Haruto and Katsumi say their farewells, promising to meet in the real world. However, when Haruto exits through the door, he awakens in the dream world bedroom once more. Seeking answers, Haruto and Katsumi attempt to uncover the mysteries surrounding the witches, Lily, and Haruto's own inability to leave the dream world.