Set during World War II in 1942, the series follows a high-stakes intelligence mission after an Allied aircraft carrying a mysterious and vital figure is shot down in Japanese-occupied territory. Faced with an impossible task, the military intelligence department reactivates a covert operative who has been dormant for five years and sends him, along with a local assistant, to infiltrate a heavily guarded island.
Under constant surveillance by occupying forces, the two must earn the trust of the island’s residents while navigating danger, deception, and shifting loyalties. As the mission unfolds within this isolated “sea prison,” survival, trust, and duty are put to the ultimate test.
