Imagine if Ocean’s 11 director Steven Soderbergh teamed up with documentary maker Michael Moore (Bowling for Columbine, Sicko) to remake Free Willy…. except with dolphins. The result would look something like The Cove; an alarming documentary on the brutal dolphin slaughtering trade in Japan. Despite a title that could easily be mistaken for a horror film, The Cove is essentially all genres rolled in a single film that yanks away at every emotional string you’ve got. It’s thrilling and chilling, amusing and moving, and if I could think of any other sensations that rhymed, The Cove would surely be those as well.

So what’s the secret surrounding the picturesque cove in the seemingly quaint fishing village of Taiji, Japan? It’s a dolphin’s worst nightmare according to marine activist Richard O’Barry, who after spending years as the animal trainer on the popular TV show Flipper, came to realise the highly intelligent mammals were never meant to be kept in captivity. It’s in Taiji that SeaWorld – and most other marine enclosures on the planet – purchase the show dolphins that you will later see flipping through hoops for your entertainment. “But they look to be enjoying themselves!” you might argue. Yet their supposed smile, O’Barry believes, “is nature’s greatest deception.”

The dolphins that are forced to work for their food are really the lucky ones. The hundreds that are not picked are taken to a highly guarded inlet around the bend where they are mercilessly culled. Of course, the Japanese Government actively deny it, and until there’s hard evidence put forward that is happening, little can be done to prevent it. It thus becomes O’Barry’s mission to get such evidence, enlisting the help of a crack team of specialists – consisting of deep sea divers, model builders (from Industrial Light and Magic), sound technicians and cameramen-  to help capture the horrific secrets of the cove on camera.

You needn’t look past the opening credit, “A film by the Ocean Preservation Society” to notice The Cove has a clear-cut agenda it wants us to be a part of.  It never comes across as pretentious, but as you’d expect, it’s hardly an objective film; whilst first-time director Loiue Psihoyos (leader of the Ocean Preservation Society) does make an effort to point out that few Japanese citizens are aware the culling occurs, the film practically stamps “EVIL” on the foreheads of the entire Japanese fishing community. Yet The Cove argues it’s point so decisively and packs such an emotional punch, it’s near impossible to not want to be a part of the solution, even if that is as simple as thinking twice before planning your next trip to SeaWorld. The film effectively puts forth the sentiment that ‘Dolphins are people, too’, only a lesser species because they lack  opposable thumbs. Each interviewee does a tremendous job of personifying the marine mammal when talking of their incredible encounters; a deeply remorseful O’Barry explains how Flipper loathed captivity so much, he believes she actually commit suicide in his arms by consciously choosing not to take another breath.

While a documentary at heart, The Cove traverses so much more terrain thanks to Prsihoyo’s astute ability to craft a compelling story out of a the limited footage they often had to physically fend off Japanese fishermen to obtain. Kudos must also be given to Geoffrey Richman in the editing room, who doesn’t merely place talking heads and stock footage into a logical sequence, but tactfully alters the pacing of his cuts when the film takes shape as a real-world spy thriller. Like something out of North by Northwest, O’Barry’s team of activists are constantly tailed and questioned by the police as they embark on midnight reconnaissance missions to the cove.  Their plan of attack is to secretly install cameras disguised as rocks in and around the cove to capture the carnage. It’s highly tense stuff, not only because getting caught could result in a lengthy jail sentence, but because failure might mean something far, far worse will occur…absolutely nothing.

Follow the author Anders Wotzke on Twitter.