Rainbow Fireflies (虹色ほたる～永遠の夏休み～, Niji-iro Hotaru: Eien no Natsu Yasumi, Rainbow-Colored Fireflies: The Eternal Summer Vacation) is a 2012 Japanese anime film directed by Kōnosuke Uda.

[1] On a hot summer day, a young boy named Yuta visits the dam where his father died one year ago.

At the site he meets a mysterious old man.

He wakes up to discover he is 30 years in the past.

There he meets a girl named Saeko, who loves fireflies, and also befriends a boy his age named Kenjo.