Journalist Mikael Blomkvist, convicted for slander, is hired by industrialist Henrik Vanger to solve the 40 year old disappearance of his niece Harriet, but Mikael soon finds out he's getting help in the case, from hacker Lisbeth Salander.

As Mikael and Lisbeth join forces to solve the disappearance of Harriet Vanger, it may turn out to be much more deadlier than that, as they try to find out what connection Harriet had with five brutally murdered young women.

Lisbeth finds out she's wanted by the police for the murder of her guardian, a woman and the woman's boyfriend, a reporter writing an expose' on sex trafficking for "Millenium", but unknown to Lisbeth, she's wanted by someone else as well.

As Mikael continues to try to prove Lisbeth's innocence to the police, Lisbeth continues to find the leader of the sex trafficking ring, but it may be the last person she would ever expect to see.

A branch of the Secret Police begins to feel threatened by the outcome of the "Zala" incident. Now, in order to protect themselves, they decide to silence those who may be considered a threat to them, including Lisbeth.