It is the first week of April 1945. The Americans are bombarding Okinawa and have landed in their tens of thousands. But on a small island remote from the terrors of battle, 16-year-old Hiromi (Lisa Oda) comes upon a cave where American deserter Bob (Brandon McClelland) has appeared. Bob is taken in by Japanese deserter Takayasu (Shinnosuke Mitsushima). Hiromi decides to look after the two men, knowing that it is extremely dangerous. Soon after, Takayasu's elder brother Hajime (Takahiro Miura) appears in the cave. Hajime, a fanatic soldier, vows to kill his brother, his enemy Bob and the "traitor" Hiromi once he recovers from his wounds. Tensions mount to what appears to be an inevitable climax of violence and murder. - We now find ourselves in 2016 in Tokyo, where a female student, Shiho (Riho Yoshioka) is handed a diary written by Hiromi. But the diary leaves some questions unanswered. Shiho's curiosity leads her to the startling truth of what really happened to the three men in the cave - and the fate of the young girl, Hiromi.