Park Yu-chun and Han Ye-Rin in "Haemoo"

There is intrigue abound well before “Haemoo (Sea Fog)” even begins, the directorial debut of Shim Sung-bo coming a decade after he co-wrote Bong Joon Ho’s breakthrough film “Memories of Murder.” Since then, Shim has been quiet while Bong became one of the world’s most celebrated auteurs with such films as “The Host,” “Mother” and “Snowpiercer,” though the two have reunited for this adaptation of a play based on a real-life incident involving a fishing crew caught smuggling illegal immigrants in international waters, something that arouses even more curiosity once Shim reveals himself to be every bit the accomplished cinemagician that Bong is.

“Haemoo” doesn’t veer far from the taut yet morally ambiguous territory of their first collaboration, setting the action in 1998 just after the IMF crisis economically crippled South Korea where a quartet of fishermen are already having trouble reeling in fish with the Junjin, a dilapidated trawler in need of a significant upgrade. In fact, the ship’s surly captain Kang Chul-joo (Kim Yoon-seok) is so down on his luck that he comes home to find his wife screwing another man, a comic flourish that becomes as much a distinction of Shim’s style as his nonjudgemental eye. Soon enough, the desperate Kang finds himself agreeing to use the boat’s fish hatch to transport a group of 25 dislocated Koreans from China, not informing his crew of his decision to make some extra cash and learning quickly that he is ill-prepared to evade detection by authorities and keep his passengers alive, providing them with just a bowl of instant ramen and some fresh water for the long journey.

The tensions between the crew and the passengers makes “Haemoo” the rare high-seas thriller where the rising tide is the least of anyone’s concerns on the ship, and once a surprise inspection leads to an unthinkable tragedy, the film transforms into a survival tale unlike any other I’ve seen before. Even with a considerable ensemble, Shim is careful to build each of the characters up to make the action matter when disaster strikes and the main crux of the film becomes the relationship between Dong-sik (Park Yu-chun), the youngest member of the crew who risks his life during the transfer of passengers on the open water to save a young woman named Hong-mae (Han Ye-rin) when she falls overboard in a particularly heartrending sequence, then feels responsible for her even after the crew and the keep suddenly are at odds.

Shim Sung-Bo's "Haemoo"Things grow increasingly hazy as the film wears on, a fog literally rolling in as Captain Kang’s desire to reassert control over his ship takes “Haemoo” into increasingly treacherous moral terrain, which Shim handles as deftly as the geography of the action on the Junjin. Although he occasionally hits a wrong note – Chan-wook (Lee Hee-jun), the horndog shiphand whose relentless pursuit of Hong-mae doesn’t quite make the leap from running gag to serious threat that the director would hope – Shim and Bong lay out such a rich array of characters with varying motives and impulses that the film only deepens once they’re called on to nakedly make decisions out of self-preservation. While Park and Han are quite appealing as the young and less corruptible Dong-sik and Hong-mae, the performance from Kim, usually a heavy in such films as “The Yellow Sea,” shows the film’s real depth as the captain whose attempt to put on a brave face as he further compromises himself to make ends meet becomes as tragic as it is fearsome.

Bong’s frequent cinematographer Hong Kyung-pyo also provides a steadying hand, never making “Haemoo” feel claustrophobic as might be the initial instinct of most, but effortlessly moving about the boat, mixing the intimacy of closeups with the grandeur the open water setting entails for the film to feel as big as the stakes it sets up while ultimately telling a small story. Add to that a seat-rocking sound mix and the result is remarkably immersive – as shocking as the end result of “Haemoo” may be, it may be even more amazing that this started life on the stage.

It’s a truly thrilling debut from Shim, who makes one bold choice after another, even when he ends the film with a hint of melancholy after staging such a breathtaking climax, and offers further proof that some of the most exciting filmmaking in the world right now is going on in South Korea.

“Haemoo” screens twice at AFI Fest in Los Angeles on November 9th at 8 pm at the Chinese 1 and November 12th at 6 pm at the Chinese 2.