Children of Iron

Children of Iron is a 2015 Japanese drama film directed by Koki Fukuyama. It was the opening film at the 2015 SKIP CITY INTERNATIONAL D-Cinema FESTIVAL and was also screened at the 2015 Tokyo International Film Festival. The film's theme song is "Otona ni Nattara" (大人になったら) by Glim Spanky.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.