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, they find it may be connected with five brutally murdered young women.

As Lisbeth and Mikael investigate a sex-trafficking ring, Lisbeth is accused of a triple murder, causing her to go on the run while Mikael works to clear her name. During his search for Lisbeth, Mikael discovers details about her past.

As Mikael continues to try to prove Lisbeth's innocence to the police, Lisbeth finds 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.

As Lisbeth's trial begins, Mikael races against time to gather information to acquit her, but The Section begins a new course of action to stop Mikael's investigation: striking out against Erika and Mikael themselves.