Ken Watanabe and Julianne Moore share the piano in Bel Canto.

International casts present a unique challenge to both viewers and filmmakers. The absence of a unifying language can be distracting, as well as the actors’ different rhythms. An archetypical example is a terrible horror movie from 15 years ago called Darkness, for which Spanish director Jaume Balagueró cast Anna Paquin (Canada), Lena Olin (Sweden), Iain Glen (Scotland) and Giancarlo Giannini (Italy) as your average American family to hilarious effect.

Bel Canto knows better. The film uses the language barrier between the protagonists for its benefit, a challenge they have to overcome in order to survive. While the movie works well as a romantic drama, it doesn’t as a thriller, a bit of a problem when you are dealing with a hostage situation.

In a no-name Latin American country (cough, Peru, cough), a party is thrown to honor rich industrialist Katsumi Hosokawa (a soulful Ken Watanabe). The main attraction is Roxane Coss (Julianne Moore, lip-synching her heart out), a renown opera singer just short of difficult. The evening is abruptly interrupted by a guerrilla group (cough, Tupac Amaru, cough) that was expecting to kidnap the President at the event… unaware he stayed home to catch up with his soaps.

A lengthy hostage situation ensues. The perpetrators, led by Comandante Benjamin (Tenoch Huerta), are depicted as freedom fighters pushed too far by a corrupt government. Meanwhile, the guests –including Christopher Lambert as the French ambassador– make the best of a bad situation, like Hosokawa and Coss, who are smitten with each other. Just for the kicks, a Swiss Red Cross operative (Sebastian Koch) becomes the mediator.

The romantic aspect of the film is the most accomplished. Both Watanabe and Moore are believable as the two ships passing in the night, same as the all-purpose translator who falls for a comely guerrillera.

The problem with Bel Canto is that falls flat as a thriller. Director Paul Weitz (Meet the Fockers) forgoes the tension of a hostage situation entirely, mutes any antagonism between terrorists and captives, and only unleashes the villain at the very end. This is not entirely the filmmaker’s fault. The movie is based on a novel by Ann Patchett, not the edgiest of writers.

Perhaps more interesting than the film itself is what it chooses to conceal. While populated by fictional characters, the story is based on the 1996 Japanese embassy hostage crisis in Lima. The name of Peru is never uttered (even though we can see badly disguised flags throughout) and the president at the time –Alberto Fujimori– is dubbed “Masuda”, while showing images on the real guy on TV. What is the reasoning behind all this? Your guess is as good as mine. 2.5/5 prairie dogs.

Bel Canto opens Friday, November 2nd at Rainbow Cinemas/Studio 7.