Diver Mandy-Rae Cruickshank swims with dolphins near a Japanese cove where the mammals are hunted and slaughtered in the environmental documentary The Cove.

If you walk into The Cove expecting an earnest enviro-doc along the lines of An Inconvenient Truth or The 11^th Hour, you're in for a surprise. In fact, director Louie Psihoyos even refuses to call his film a doc.

“This is a thriller with the heart of a documentary,” Psihoyos explains during a recent promotional visit to Toronto. “So you're going to get your vegetables, but you're not going to notice, because you're seeing a classic thriller.”

The documentary The Cove delivers more edge-of-your-seat moments and high-tech gadgets than Quantum of Solace and Ocean's 11 combined.

If that sounds immodest, well, The Cove delivers more edge-of-your-seat moments and high-tech gadgets than Quantum of Solace and Ocean's 11 combined. It's a stunningly effective heist movie, but instead of stealing cash or diamonds, Psihoyos and his team attempt to capture gruesome video images of the annual dolphin slaughter in Taiji, Japan – “a little town with a really big secret,” as one American dubs it.

It turns out that dolphins – both dead and alive – propel the local economy. Some of the smiling cutie-pies fetch $150,000 each when they're sold to tourist attractions and “swim with the dolphins” businesses around the world. The unlucky ones are killed and sold for $600 apiece, their mercury-laced flesh often fraudulently passed off as whale meat.

From September to March each year, Taiji fishermen kill 23,000 dolphins in an out-of-the-way cove using a variety of spears, knives and hooks. It's brutal, gut-churning stuff, and naturally, they don't want the visuals broadcast to the world. As a result, the killing zone has round-the-clock security.

Enter Psihoyos and his international crew of deep-sea divers, underwater audio-video experts and self-professed “adrenaline junkies.” The first-time director, who honed his storytelling chops as a National Geographic photographer, laughs when he recalls his rookie naiveté. “I was too stupid to realize that [trying to film the slaughter] was going to be a monumental task. Trying to make a film in the best conditions is tough, but trying to make it in the worst, at night, with people on your tail who want to arrest you, who might want to kill you – the complexity was overwhelming.”

Marine mammal specialist Ric O'Barry is a dolphin trainer turned environmental activist. (Maple Pictures)

Watching the film, their venture feels like an elaborate, almost military mission. Funded by billionaire Jim Clark (creator of Netscape and Silicon Graphics), the team even enlists special effects heavyweight Industrial Light and Magic to create fake rocks with built-in cameras. Armed with these tools of the cloak-and-dagger trade, they make various nocturnal forays into the cove – spine-tingling moments in which they clearly place themselves in harm's way. Attracting the attention of pissed-off fishermen and the Taiji police is worrisome enough, but there's a strong suggestion throughout the film that the Japanese mob – the Yakuza – has a proprietary interest in the slaughter.

Psihoyos's film pays particular attention to one member of his squad: Ric O'Barry, the trainer of the five dolphins who starred on the 1960's kids adventure show Flipper. Now 69, O'Barry gives The Cove its moral spine. He's a compelling figure, seemingly wracked with guilt over the role he played in creating a demand for captive “show dolphins.” Since 1970, O'Barry has travelled around the world, including several previous trips to Taiji, in an endless quest to undo his earlier work. He releases the animals wherever he can, and draws attention to what he sees as the inherent cruelty of putting them on display at amusement parks. According to O'Barry, the sonic environment in these tourist attractions is akin to torture for dolphins, whose hearing is highly sensitive.

The intensity he displays in the film is also evident in person. “This movie points out things that we've never considered before. Places like Marineland, Seaquarium and Seaworld are a $2 billion-a-year industry in the U.S., and they have a lot of power in advertising. They have people believing that dolphins belong in these concrete boxes. The dolphin's smile is nature's greatest deception. It creates the illusion that they actually like doing this job, like they actually volunteered for it. So the whole industry is based around this optical illusion.”

The Cove has already been a crowd-pleaser on the North American festival circuit, winning audience awards at Sundance and Toronto's Hot Docs and generating Oscar buzz along the way.

Director Louie Psihoyos, Charles Hambleton and Joseph Chisholm engage in a covert mission to capture images of the annual dolphin slaughter in Taiji, Japan in the film The Cove. (Maple Pictures)

O'Barry is obviously pleased at the response, but not overly impressed that his personal story is gaining so much exposure. “That doesn't mean anything to me. What's important to me is getting this film in front of the Japanese people, so they can make intelligent decisions as to whether they want to continue buying tickets for a trained dolphin show.”

It's made clear in the film that the Taiji operation is unknown throughout most of Japan. Both Psihoyos and O'Barry believe that getting the film shown there will help put pressure on the Japanese government to end the massacre.

“We're working on it feverishly,” says Psihoyos. “There's an American businessman who gave us $70,000 last week so we could get it dubbed. The guy who voices Robert De Niro in Japan is doing my voice.”

While he was in Toronto, Psihoyos learned that the Tokyo Film Festival rejected the film – probably due to its harsh criticism of Japan's environmental policies. It's an ironic development, considering the theme for the Tokyo film fest this year is the environment.

Still, there's always the internet. “Jim Clark has the power to get this movie to the Japanese people on the web for free,” notes O'Barry. “He told me he would do that as a last resort. He would like to get it in theatres, because it really is a theatre experience and the Japanese are very community-oriented.”

No matter the status of the film's distribution, O'Barry will return to Japan on Sept. 1, when the Taiji ritual begins again. “I don't know what's going to happen,” he says. “I may be able to get in, but I don't know if I can get out. That may be more difficult. I understand there's an arrest warrant out.”

The Cove opens in Toronto on Aug. 7, Montreal on Aug. 14 and Vancouver on Aug. 21.

Greig Dymond writes about the arts for CBCNews.ca.