Japan, 1944. Trained for intelligence work, Hiroo Onoda, 22 years old, discovers a philosophy contrary to the official line: no suicide; stay alive whatever happens; the mission is more important than anything else. Sent to Lubang, a small island in the Philippines where the Americans are about to land, this role will be to wage a guerrilla war until the return of the Japanese troops. The Empire will surrender soon after; Onoda, 10,000 days later.

Mizuki’s husband Yusuke went missing for 3 years. He suddenly comes back home one day and asks Mizuki to go on a trip with him. Their trip consists of visiting the people that helped Yusuke on his previous travel. While travelling together, Misuki sees, touches and feels what Yusuke did for those 3 years.