Why was the family erased?

When the suspect of an arson case refuses to cooperate with the investigation, the detectives search his house and find a locked-up little girl. She doesn't talk and there are no clues to her identity, so assistant psychology professor Narumi Saku is asked to counsel her.

Kuttsukiboshi centers around two girls' "risky" summer vacation together. Kiiko is your normal girl, besides her secret of being able to move objects with her mind. When a new student named Aaya moves in, Kiiko starts to develop feelings toward her. The two will eventually then start their romantic relationship. Although everything seems fine, Kiiko does not know that Aaya has another secret, a secret that could ruin Kiiko's feelings and trust for Aaya.