Manipulation. Abuse. Murder. The women's prison Flodberga is ruled by a strict regime. Everyone listens to Benito Andersson, the undisputed leader of the inmates. Lisbeth Salander, who is serving a short sentence, tries her best to avoid contact, but when her cellmate is bullied, she intervenes and finds herself in the crosshairs of Benito's gang. Meanwhile, Holger Palmgren, Lisbeth Salander's longtime mentor, has uncovered documents that shed new light on Salander's childhood and her abuse by the authorities. Salander asks Mikael Blomkvist to assist her in the investigation. A request she soon regrets.