Exciting action, strong stars carry 'Bourne Legacy' well

It's not the same ultra-high-caliber espionage thriller without Matt Damon sprinting around the globe or masterful director Paul Greengrass in charge, but The Bourne Legacy (* * * out of four, rated PG-13, opens Friday nationwide) is a brisk and challenging film.

Where 2007's The Bourne Ultimatum kicked off with a dazzle that never let up, Bourne Legacy starts slowly and takes a while to connect the dots. But once the story takes off, it's viscerally engaging, anchored by strong performances, with Jeremy Renner as a capable heir apparent.

The title may seem misleading, since Bourne is only talked about here. He's supposedly spotted in New York by the powers that be, but not by the audience. The story, which expands upon the clandestine world of trained killers, is triggered by events from the previous films.

Renner plays Aaron Cross, a slick super-spy and Iraq War vet. Though he doesn't have as much charisma or nuance as Damon did, he projects a steely intensity juxtaposed with moments of vulnerability that make his character appealing.

But we get only droplets of his back story. Director Tony Gilroy, co-writer of the three previous Bourne films, knows this universe — created by novelist Robert Ludlum— backward and forward and should have further fleshed out Cross' character.

Legacy spins off where Ultimatum left off. When last we saw Bourne, he and Agent Pam Landy (Joan Allen) exposed the top-secret Treadstone government project.

The film kicks off amid a CIA frenzy. Nefarious top brass such as Col. Eric Byer (Ed Norton) seek to minimize further exposure of their dark plans by shutting down the elite spy programs formed to create assassins. The agents at risk this time are in a related Defense Department program called Operation Outcome, and their numbers include Cross.

He is being groomed as an enhanced spy, daily ingesting "chems" that boost his intelligence, endurance and resistance to pain. When we first see him, he's alone in a remote corner of Alaska. Then the action switches back to Washington, over to Asia and the Middle East, and ping-pongs headily between shady high-level CIA bureaucrats and operatives around the world.

The dense tale can be hard to follow for the first half-hour, until a disturbing shooting takes place in a lab where Marta Shearing (Rachel Weisz) is a doctor assigned to monitor Outcome field agents.

Single-handedly fending off drones sent to kill him as well as wolves, Cross makes it from Alaska to Shearing's home in Maryland in a desperate search for meds.

Weisz is a smart addition to the Bourne-sphere. An actress who conveys an astute intellect, she seems as convincing spouting medical jargon as she does pulling off action stunts.

Though there definitely is suspense, the movie suffers from moments of lethargy and lacks the explosive urgency of previous installments.

This latest Bourne doesn't send adrenaline surging the way Ultimatum did, but it's still a tense, well-acted thrill ride.