Those familiar with Fang Li's 2023 documentary about the “Lisbon Maru,” a freighter transporting over a thousand British prisoners of war from Hong Kong to Japan before being struck by a US submarine, will already know that the treatment inflicted upon those captives by their jailers was shockingly cruel—and that’s putting it mildly. This dramatization instead concentrates on the harshness displayed by the occupying forces on a nearby Chinese island, where local people were under the control of a small military group and forbidden from using their fishing boats. The story follows two brothers, rumored to have pirate ancestry, who disregard this restriction, and during one such trip, “Bi” (Yilong Zhu) and “Dang” (Lei Wu) find “Newton” (William Franklyn-Miller), weak and starving, adrift in the water. One brother believes they should avoid involvement, while the other wants to rescue him; after a brief struggle and some improbable maneuvers, “Newton” is brought ashore, becoming the target of a search initiated by forces now led by an especially brutal young officer. Simultaneously, the damaged ship continues to sink, and as the islanders witness the smoke and hear the explosions, they decide to set sail despite facing overwhelming force, attempting to rescue those in the water who are regularly being mowed down by machine-gun fire. The film incorporates a noticeable amount of CGI that isn’t particularly impressive, but it successfully blends historical events with the bravery of the fishermen and touches of fantasy—the two brothers possess astonishing diving abilities, able to hold their breath and battle currents with remarkable skill—and maintains a consistent rhythm throughout. The calculated violence and savagery of the antagonists are effectively portrayed, and the characterizations of the two brothers are compelling as their journey, along with that of the spirited “Hua” (Ni Ni), takes them out to sea and directly into danger. The film’s overall message occasionally evoked comparisons to "Bridge over the River Kwai" and "Tenko," highlighting the oppression experienced by a community seemingly unchanged for generations and ill-prepared to confront the rifle-wielding group of aggressors who seized control of their island simply because they could, viewing the inhabitants with utter disdain. It does run a bit long, and there’s a noticeable element of modern patriotism in its style and presentation, but it keeps an important story alive and functions reasonably well.

Source on TMDB