Rainbow Fireflies

Yuuta, a 12-year-old boy, is struggling to cope with the loss of his father, who passed away in a traffic accident a year prior. When he visits the deserted dam in the mountains, a place where he spent a happy summer with his father, a severe thunderstorm hits and Yuuta falls, losing consciousness. Upon waking, he finds himself in a strange village with a girl, and to his shock, discovers that he has traveled back in time 30 years, arriving in a village that once existed at the bottom of the dam.