A graphic novel of the upcoming film from Mamoru Hosoda of "Summer Wars" fame. Kun is apprehensive about his new baby sister, thinking his parents will love him less than they used to, but when a teenage girl visits him claiming to be his sister from the future, the potential of their relationship is proved to be greater than Kun could have imagined.

Mamoru Hosoda is an internationally acclaimed animator, director, and author who has previously helmed such award-winning films as The Girl Who Leapt Through Time, Summer Wars, Wolf Children, and The Boy and the Beast.