In the town of Saima, when summer is about to begin, a group of six high school students intend to live a secret adventure by spending seven carefree days in a ruined mining facility.

A shy high schooler in Kyoto meets a man claiming to be his future self, who tells him he’s hacked into the past to save their first love.

Spin-off of the movie Hello World which is narrated from the point of view of the character of Naomi. The story is located 10 years in the future.