The surprise hit "Taken", from 2008, contained a number of red meat pleasures, but chief among them was Liam Neeson's reinvention as an action hero, turning his trademark wounded brusqueness and gentle-giant physique towards new, head-clunking avenues. Despite an ad campaign that makes it appear to be a direct action-packed continuation of that earlier film, "Unknown" proves to be a somewhat different creature--a sleek mystery that occasionally gives in to temptation and lets its hulking star call down the righteous thunder. Based on a novel by Didier Van Cauwelaert, the story follows a mild-mannered botanist in Berlin with his wife ("Mad Men"'s January Jones) for a mysterious scientific conference. After a freak car accident, he wakes up in the hospital with scrambled memories, missing identification, and--most ominously--someone else claiming to be him. Director Jaume Collet-Serra, previously responsible for the admirably berserko "Orphan", handles the early paranoiac cloak-and-dagger passages with aplomb (and delivers one quick beaut of a car chase), but proves less sure-footed when the story drifts towards more conventional "Bourne"-style punch-ups. Thankfully, Neeson does a fine job keeping things grounded whenever the narrative starts to wander, with able support from Diane Kruger as a cab driver unwillingly along for the ride. There's the germ of a genuinely intriguing, thoughtful thriller inside "Unknown"--particularly during a superbly minimalist scene between supporting cast members Frank Langella and Bruno Ganz--but it mostly seems content to stay within the realm of a high-pedigreed, reasonably taut action film. Which isn't all that bad of a thing, really. "--Andrew Wright"