The Eternal Zero is a 2013 Japanese drama film directed by Takashi Yamazaki. The film depicts the story of a young man named Kentaro Saeki who is struggling to pass the bar test and his older sister Keiko who is a freelance writer. The siblings are curious about their grandfather Kyuzo Miyabe who was a member of the Japanese Special Forces during World War II and died in the line of duty.
Kyuzo Miyabe was known to be a genius among his navy comrades, but he was also considered a coward due to his strong fear of death. His family and comrades could never understand why he volunteered for the Special Forces. Kentaro and Keiko commence a journey to uncover the truth about Kyuzo Miyabe's life and death.
As they start their quest, they learn about his childhood and how it influenced him to pursue a military career. Eventually, they discover that Kyuzo Miyabe was forced to make an impossible decision that led to his death and honor.
Throughout their journey, Kentaro and Keiko gain a new appreciation for their grandfather's bravery and selflessness. They also gain an understanding of their own family's history and identity.
Overall, the film explores themes of sacrifice, duty, and honor in the context of an individual's personal struggle.