Pour l'Empire du Soleil Levant, la guerre est sur le point de finir. Pour Onoda, elle s'achèvera 10 000 nuits plus tard.
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.