David Lagercrantz continues Stieg Larsson's Millennium series with this Lisbeth Salander novel that is the sixth in the series.

Lisbeth Salander has disappeared. She's sold her apartment in Stockholm. She's gone silent electronically. She's told no one where she is. And no one is aware that at long last she's got her primal enemy, her twin sister, Camilla, squarely in her sights. Mikael Blomkvist is trying to reach Lisbeth. He needs her help unraveling the identity of a man who lived and died on the streets in Stockholm--a man who does not exist in any official records and whose garbled last words hinted at possible damaging knowledge of people in the highest echelons of government and industry. In his pocket was a crumpled piece of paper with Blomkvist's phone number on it.