I liked this one much more than #5, also written by Lagercrantz.  Maybe it was me, maybe Lagercrantz is hitting his jam in this series he has continued.  At any rate, Lisbeth  is up to her old tricks - being the superhero nerd character that I fell for from the start.  Mikel gets swept up in a political issue that reaches its icy fingers back to a Mt Everest climb from years before.  Lisbeth is tracking her sister. And all the threads weave in and out of the novel in a seamless way.