Niji-Iro Hotaru: Eien no Natsu Yasumi (2012)
Niji-Iro Hotaru: Eien no Natsu Yasumi, English title Rainbow Fireflies, is a 2012 Japanese anime film directed by Kōnosuke Uda.
More at Wikipedia.
Director: Kōnosuke Uda
Release date: May 19, 2012
External links:
Official site