High school student Mizuki Mochizuki is in love with British rock artist Adam Lang, but it seems that he cannot see her for who she is, as he is still grieving the death of his ex-girlfriend, Sayaka Kamijou. Despite this, when Adam asks Mizuki over the phone to leave Tokyo with him, she agrees to meet him immediately. But as Mizuki crosses the road toward Adam, a car strikes her, and she fails to reach him.

One month later, a Mizuki lookalike is living in the abandoned mansion where Mizuki and Adam had spent two weeks together. While fifth-grader Hotaru Shiraishi is searching for her missing cat, she runs into this other girl and learns that her memories are gone—she cannot even recall her own name. Since the girl only remembers that she wants to be reunited with "Adam," Hotaru calls her "Eve." Hotaru enlists the help of her friend Sae Kayama and classmates Tetsu Sugisaki and Masaki Miura to solve the mysteries surrounding Eve—but they claim to be unable to see her!