Hell to Eternity.

Based on the story about Guy Gabaldon, a Los Angeles Hispanic boy raised in the 1930s by a Japanese-American foster family. After Pearl Harbor, his foster family is interned at the Manzanar camp for Japanese Americans, while he enlists in the Marines, where his ability to speak Japanese becomes a vital asset. During the Battle of Saipan, he convinces 800 Japanese to surrender after their general commits suicide.