"Awake" is a thriller about a billionaire who overhears a plot against him while under anesthesia.

Hayden Christensen is the billionaire. He's anxious to get a heart transplant because, well, he has Jessica Alba to wake up to.

This is a medical thriller that packs an awful lot of plot and plotting into a compact 78 minutes.

Who's out to kill poor Clayton Beresford? Is it the Japanese mob-connected corporate sharks who want to merge with the company his dad founded? Is it his possessive mom (Lena Olin)? Greedy surgeons? Hey, they cast that human ferret, Fisher Stevens, as one of them. My money's on him!

Not to worry. Beresford's surgeon (Terrence Howard) is his pal, the guy who takes him fishing on the banks of the East River. And again, there's Alba, the hottie he's been bedding and hiding from his mom, to nurse him back to health.

Christensen, who still hasn't shed that Bob Dylan voice he showed off in "Factory Girl," is a man suffering from "anesthesia awareness." He's put under by a tipsy anesthesiologist (Christopher McDonald), so he feels everything. Chest shaved and cut, ribs spread.

Much of writer-director Joby Harold's film has Christensen voicing-over the graphic heart transplant, trying to piece together the puzzle presented by what he overhears, ruminating over flashbacks, hunting for clues as to who or what is behind this scheme.

Harold's script has a surprise or three in it, a biggie near the end. But he's a director with no poker face. He tips his hand early and often.

And all of this is underscored by Christensen screaming, "It's just pain. It's JUST PAIN. FOCUS," while on the operating table. That'll make you squirm.

There are good scenes and clever bits of dialogue ("Here, you wanna plant that?" is how Howard handles the new heart) mixed in with lots of Screenwriting 101 blunders. Characters recite the memorized resumes of each other to "prove" they know who they are, a common and trite scripting shortcut.

"Jack Harper. Two divorces, two ulcers. You still fish on the East River?"

The bigger problem is Christensen, who has had a most uneven career since his "Star Wars" discovery, nailing the occasional "Shattered Glass" and "Factory Girl," but often in over his head, as he is here.

And by the time somebody blurts out, as they always do in these dramas, "We're losing him," the movie loses us.

Thus, while "Awake" isn't a snoozefest, it's nobody's idea of a sleeper hit, either.