Hanna is about a girl (Saoirse Ronan) who has been raised by her father Erik Heller (Eric Bana) in a cabin in the woods of Finland. She has never met another person besides her father, but he has prepared her well for survival. She knows several languages, she can defend herself and kill with ease, and he has even given her a back story in case she is ever questioned.
Her father was some kind of CIA agent who disappeared, and as the movie progresses we find out why. For some reason that I didn't feel was fully explained, Erik gives Hanna the choice of activating a homing beacon. Once activated, another agent named Marissa Wiegler (Cate Blanchett) will come after her and try to kill her. Even by the end of the movie, I wasn't quite sure why he would want Marissa to come after Hanna. If he wanted Marissa dead, I would think there are easier ways to go after her.
His plan seems to be a horrible one. He will leave Hanna alone in the house while assassins come to the cabin (following the homing beacon). He will be long gone, but Hanna will be captured. She will escape and the two will meet up again in Berlin at a really cool looking Grimm's fairy tale house. If the whole plan was to kill Marissa for what she did to Hanna's mother, I would think he could come up with a better way to do it. This plan requires a lot of killing and the constant threat to both of them of being re-captured or killed.
One interesting thing is how many people Hanna and her father kill. She has been trained since birth to be an assassin, so she has no problem killing. But luckily somehow she is not a psychopath. When she meets another girl her age, she becomes friends with the girl and her family.
But any agent who gets in her way (or Erik's way) is quickly killed. In movies like this, you have to assume that all the CIA agents are bad guys. But I couldn't help thinking that most of them were under the assumption that they were after some rogue agent, and their orders were justified. There is even a sequence where Erik kills a couple of cops who happen upon him when he swims ashore in Germany. As far as I can tell, they just happened to be there. It's hard to sympathize with the protagonist when he is killing cops.
Besides that, this was a really cool movie. There were some good fight scenes, and it was well choreographed. Not like most action movies that are so over edited, you can't tell what's going on. In this movie, I always had a clear sense of geography. There were some clever and fun sequences with inventive camera moves. Particularly good was the scene where Erik overpowers a bunch of guys in a train station. The entire scene seemed to play out in one long tracking shot.
The only problem with the movie is the marketing. The trailers are showing all the action scenes, and audiences are going to be surprised by how slowly this movie moves. Instead of wall to wall action, there are a lot of quiet scenes of Hanna walking, or hiding, or experiencing the outside world for the first time. The movie does move slowly in places, but I was never bored.