RIDLEY Scott is back in the Middle East for a third time with Body Of Lies, a morally murky war-on-terror movie which also strikes a universal chord by creating a central character who can speak 12 languages, and gripe about the boss in all of them.

Leonardo DiCaprio applies one of cinema's most unlikely beards for his first appearance as Roger Ferris, a key agent on the trail of an emerging terrorist leader, Al-Saleem (Alon Abutbul). The pointy end of the spear against terrorism, Ferris knows the areas, the people and the cultural complexities. But because he's constantly undermined by his line manager, Ed Hoffman (Russell Crowe), he's also constantly on the run, dodging bombs, bullets and even angry dogs.

Hoffman is an arrogant CIA technocrat willing to sacrifice or expose a contact to gain the upper hand. After interrogating a hopeful Iraqi defector in the middle of the desert, Ferris calls Hoffman to get the informer put under US protection. Instead Hoffman tells Ferris to put him back onto the street so they can watch who comes after him.

From his suburb in Washington, Hoffman jerks the chains of his field agents from his Bluetooth phone. Day and night, he's multi-tasking, barking out commands while attending his daughter's football match or helping his young son go to the toilet. You hope for the sake of the free world that his mobile is encrypted – but more than anything you suspect that the phone business is really a slightly clunky metaphor: Hoffman is a man who is only remotely connected to the realities of Middle East espionage that face Ferris.

Scott's thriller is both slick and watchable, building tension in a landscape of deserved paranoia and horrific violence. His chases through Third World slums, helicopter attacks and countdowns to things that go bang are all relentlessly exciting, while his overhead views of crowded Middle Eastern cities are vivid enough to make Google Earth hiss with envy.

You never get lost in the physical geography of a Scott film because he can establish place and space in a few swift shots. However, the narrative geography is more convoluted, partly because the film mistakes woolly plotting for intellectual complexity. Nor is it as topical as it pretends: subtract the Iraq references and what you're left with is the Parallax View Big Book Of Betrayal, as well as slight exasperation with DiCaprio's character's anguish over his clandestine anti-terrorist initiatives in the Middle East. He signed up as an undercover agent: what bit of that did he think was going to be open and above board?

Ferris also has a love interest, a pretty nurse (Golshifteh Farahani) who comes across as a bit of a sop for the ladies in the audience in case we get all fretful that no one is discussing shoes between explosions. Still, she's handy to have around, given the amount of shrapnel Leo collects in the course of the film. "Bone fragments," says one doctor, as he drops something into the dissection tray. "Don't worry, not yours."

On the whole, the performances are good – although perhaps it's time someone told Crowe that his sexy grandpaw act of looking roguishly over the top of a pair of spectacles is getting a little familiar after Beautiful Mind, while DiCaprio's pained intensity is also recognisable to those of us who saw his undercover agent in The Departed. The craftiest draw is British actor Mark Strong, who gets a chance to combine two of his specialities: looking great in Savile Row suits (RocknRolla) and playing Arabs with a propensity for beating up big Hollywood actors (Syriana).

As Hani, the head of Jordanian intelligence, he is marvellously ambiguous. Either he's an urbane creature of conscience set up to contrast with Crowe's morally flabby American counterpart, or he may be a sophisticated double agent working both sides of the souk. He's certainly compelling, especially when Hani tells Ferris that as long as he is always honest with him, all will be well. Let's remind ourselves what this movie is called. The film is one big web of side-deals and shady sub-operations.

• On general release from Friday