Star sand (2017)

In the closing days of World War II, Japanese-American Hiromi, a girl age 16, encounters an American deserter, Bob, and a Japanese soldier, Iwabuchi, living together in a cave on a small island in Okinawa. The two men are deserters from their armies; yet both vow never to harm another human being again. Hiromi looks after the deserters until another soldier appears and the peace of the cave is shattered. It leads to the death of three of them and a fascinating mystery that isn't solved until the present day.