Waking up in a strange bedroom in a dream world, teenager Haruto Tsukishiro finds a strange app on his phone. When he activates the program, an odd woman appears and tries to drag him to her realm. Luckily, a mysterious, white-haired girl severs their connection and helps him escape, revealing that the woman is a witch; however, their conversation is cut short. As Haruto enters the realm again, he meets an anthropomorphic, talking cat named Katsumi Kanzaki. While the witch's minions pursue them, the white-haired girl opens a door for them to escape.