"Unknown" is a difficult movie to discuss.

There's a fine line between delving into this mystery and giving away too much of the plot. The best way to enjoy this Hitchcock- ian-type thriller is to watch each intriguing scene unfold.

What's safe to say is Dr. Martin Harris (Liam Neeson) and his wife (January Jones) arrive in Berlin on a snowy day to attend an international technology conference. Before the convention even starts, a car accident leaves Harris with a head injury.

He recovers to discover someone else has taken over his life – from his name to his job. Even his wife doesn't recognize him. The quest by Harris to find the truth ends up as perilous as it is perplexing.

Director Jaume Collet-Serra ("Orphan") has created a tantalizing cinematic puzzle based on the smart script by Oliver Butcher and Stephen Cornwell.

Fans of this genre will be able to guess bits and pieces of what's going on. But the storyline takes so many twists the ending's a true surprise.

Just like Alfred Hitchcock, Collet-Serra creates such a strong sense of tension that even strangers on the street appear suspicious.

The key piece is Neeson.

Just as he did in "Taken," Neeson is forceful and determined while still maintaining a degree of vulnerability. The action scenes create a few questions, but the mystery is clear by film's end.

January Jones is the biggest flaw. The nature of her role requires aloofness, but she comes across as bland. Even when she shows a different side, she's lifeless next to Neeson, Frank Langella, Bruno Ganz and Diane Kruger.

Consider Jones' work a bump in a brilliant mystery. The movie is loaded with action and is still smart enough to keep the audience guessing until the very end.