A team of treasure hunters, financed by wealthy American patriot Warren Price, ventures into a remote Indonesian island searching for Yamashita's Gold, a legendary stash hidden by Japanese forces during World War II. Accompanying the team are an ex-military tough guy, a local guide with crucial knowledge of the terrain, a historian specializing in wartime relics, and a medic. Their journey takes a dark turn as they discover an old Japanese bunker believed to hold the prized treasure. Their excitement soon shifts to trepidation when they accidentally trigger a series of traps, sealing themselves inside the fortified underground labyrinth.

As they delve deeper into the dark, claustrophobic corridors, they encounter eerie signs of past inhabitants, including remnants of gruesome wartime experiments performed by Unit 731. The atmosphere quickly becomes tense as personal motives clash and the relentless dangers of the bunker strain their resolve. Strange noises and shadows hint at a sinister presence lurking within the tunnels. The group struggles to maintain cohesion and sanity while trying to uncover an escape route. Tensions reach a breaking point, revealing true loyalties and testing their will to survive the increasingly perilous environment.