The Eternal Zero 2013

Kentaro Saeki (Hauma Miura) has failed his bar exam again. Unsure of his way in life, he then learns at his grandmother's funeral that his grandfather he thought of as a blood relative was none of the sort. His real grandfather, Kyuzo Miyabe (Junichi Okada), perished at the end of the World War II in a last minute Kamikaze mission. 

Kentaro embarks on a search for the identity of his real grandfather. However, his visits to war veteran colleagues of his grandfather yield only the grim report that he was the biggest coward in the whole navy. It appears that despite being a matchless pilot, he was more focused on making it home than taking part in combat. When the dogfights developed, he opted to avoid getting caught up in them and flew away. His motivation turns out to have been the singular promise he made to his wife Matsuno (Mao Inoue) to return home to the family at any cost. The big mystery is then why such a man would volunteer for a Kamikaze mission? As Kentaro draws nearer to those who took part in the final events of Miyabe's life, he learns just what drove the man. In this way, the message that Miyabe committed to with his life, is finally bequeathed to a new generation.