Liam Neeson plays Bryan, a retired CIA operative in the James Bond mold. He's living in LA to be close to his seventeen-year-old daughter, Kim. Kim is living with his ex-wife Lenore, who bitches at him for the first 15 minutes of the movie. Lenore had left him for a wealthy businessman who can afford to do things like buy her a horse for her birthday.
Kim wants to travel to Paris with her friend Amanda. Lenore encourages them while Bryan objects: the world is a dangerous place for 17-year-olds to go running around unaccompanied. Bitchiness ensues. Bryan relents on the condition that he receive a complete itinerary, addresses, phone numbers, and regular phone calls. He doesn't: seeing them off at the airport, Bryan learns for the first time that Kim's and Amanda's plans are to follow U2 on a European tour. "All the kids are doing it," says Lenore.
In Paris, the girls share a taxi from the airport with a charming young man who makes plans to meet them later. Amanda tells Kim that she plans on sleeping with him. (In this context, we learn that Kim is still a virgin.) Amanda has poor taste: the young man turns out to be a scout for Albanian mafiosi, who kidnaps foreign women traveling alone and forces them into prostitution.
Kim is on the phone with her father when the Albanians arrive; he thus obtains a description of the kidnappers. Bryan promptly flies to Paris to track down his daughter. Mayhem and violence ensue. (The French police turn out to be on the take.) Bryan captures an Albanian gangster who tells him, after being properly "motivated", that Kim, as a virgin, will be auctioned off to a rich Arab sheik. Amanda, in contrast, is drugged and raped to death.
Let's review. Bitchy, faithless ex-wife: check. Teen slut receives her comeuppance: check. Immigrant scum: check. Torture: check. Feckless Frenchmen: check. Like I said, this is embarrassingly perfect. Even I would have thrown liberals a bone somewhere.
Now the bad. I very nearly abandoned the movie during the early scenes. The frenetic pacing was inappropriate for Bryan's supposedly peaceful retirement. The dialog the screenwriters use to communicate the backstory is implausible. Bryan works a security detail for a pop diva, but this doesn't seem authentic even by the standards of The Bodyguard, let alone In the Line of Fire.
The movie improves dramatically after the kidnapping, but even here there are problems. As several critics have remarked, the film owes much of its pacing and action scene style to the Bourne films. This wouldn't be a bad thing, necessarily. The problem is that at 57, Neeson has visible difficulty carrying this off. Age matters (trust me on this), and what Matt Daemon can do in his 30s is not appropriate for a man in his 50s. Neeson would have been better served by the style of, say, Man on Fire, in which Denzel Washington plays a gravely injured ex-CIA agent who uses careful planning instead of raw physical prowess to rescue the girl. (The movies are also thematically similar, which would have invited unfavorable comparisons.)
Seventeen-year-old Kim is played by 26-year-old Maggie Grace. Grace overcompensates for this miscasting by aping the awkwardness of a young teen that hasn't quite grown into her own body; unfortunately, the effect makes her come across as developmentally disabled. This was disappointing. If the filmmakers wanted to highlight Kim's youth and innocence, they would have been better served by an actress that was actually young and innocent.
But these are small quibbles. I would still recommend the movie, but be prepared to be annoyed for the first 15 minutes or so.