Ai Ohto, a junior high school student who is temporarily not attending school following the suicide of her close friend Koito Nagase. During a late-night walk, Ai visits a deserted arcade, where a mysterious voice guides her to a gachapon machine that dispenses a "Wonder Egg". That night, Ai is drawn into a dream world where the Wonder Egg cracks open to reveal a girl, whom Ai must protect from a horde of monsters called "Seeno Evils". When the voice tells Ai that saving enough people in this world may bring Koito bac