A vaguely disreputable thriller about a traveler who has lost at least some of his memory, "Unknown" invites snarky comments about star Liam Neeson, whose latest films have been revenge potboilers and lowbrow TV adaptations. Has the dignified actor, who used to headline such ambitious dramas as "Schindler's List," simply forgotten who he is?

Here he plays a biotech researcher ("Doctor Martin Harris," he says frequently, placing odd emphasis on his title as if trying to pick gold-diggers in a bar) who gets separated from his wife while bound for a conference in Berlin. Injured in a cab accident, he awakens from a coma to find that his wife (January Jones) doesn't know who he is — and that a stranger (Aidan Quinn) has convinced everyone, wife included, that he's the actual Dr. Harris.

What's going on here? If Neeson is temporarily deranged, why does he know such intimate details of Martin's life? If it's all some strange conspiracy — as plenty of background details suggest — how has his wife been forced to participate? And if Neeson is destined to work it all out and reunite his family, why did the filmmakers present him with a beautiful Bosnian cabbie (Diane Kruger ) to help him evade capture while piecing the clues together?

Director Jaume Collet-Serra makes worthwhile attempts to brew some paranoiac tension (like a barely tilting camera conveying the sense that Neeson's world is being stolen from beneath him), but the screenplay is missing some nuts and bolts.

We might be tempted to ignore the faults midway through, with the welcome arrival of Bruno Ganz , as a former Stasi spy turned private investigator. As he conducts his own investigation away from Neeson, Ganz practically invents his own parallel, more intriguing movie — one that's credibly tied to the history of this wintry Berlin and more amenable to the spy-vs.-spy frippery "Unknown" eventually wants to deliver.

But the aging "Wings of Desire" star wouldn't sell popcorn or movie tickets, so attention quickly returns to Neeson and that hoary amnesia-story device — the second blow to the head that restores lost memories. Let's hope something similar happens to the actor himself, who has strayed so far from his early career that next year he'll be in theaters — this is not a joke — playing an admiral in a movie based on the old Hasbro game "Battleship."

"Unknown"

Our grade: C

Genres: Drama, Thriller

Running Time: 113 min

MPAA rating: PG-13

Release Date: Feb 18, 2011