Lisbeth Salander has broken all contact with Mikael Blomkvist, even though the hacker uses her own methods to keep track of what the journalist is doing. She is currently taking on the NSA, hacking the US interrogation service, and gathering evidence of conspiracy within the foreign intelligence service. Meanwhile, Blomkvist is no longer taken as seriously as a journalist because he has lost his bite. But when Frans Balder, one of the world’s leading experts in artificial intelligence, is murdered, his journalistic curiosity is reawakened. Because Balder had previously contacted him. In his research, Blomkvist soon finds a connection to Lisbeth. Together they have to protect Balder’s life-threatening, autistic son August, but they have a dangerous opponent: Lisbeth’s twin sister Camilla.