Fans of Stieg Larsson’s captivating odd couple of modern detective fiction — the genius punk hacker Lisbeth Salander and her sometime partner, the crusading investigative journalist Mikael Blomkvist — will not be disappointed by the latest installment of their adventures, written not by their creator, Stieg Larsson (who died of a heart attack at the age of 50 in 2004), but by a Swedish journalist and author named David Lagercrantz. Though there are plenty of lumps in the novel along the way, Salander and Blomkvist have survived the authorship transition intact and are just as compelling as ever.

“The Girl in the Spider’s Web” finds the pair drawn into the case of the enigmatic computer scientist Frans Balder: a prominent expert in artificial intelligence who’s become ensnared in a global intrigue involving the Swedish Security Police (Sapo), the Russian mob, Silicon Valley industrial spies and United States national security interests.

Mr. Lagercrantz’s efforts to connect unsavory doings in Sweden to machinations within America’s National Security Agency are strained and fuzzy — a bald attempt to capitalize on Edward J. Snowden’s revelations about the agency and the debate over its surveillance methods. But then, readers weren’t smitten by “The Girl With the Dragon Tattoo” because of its plotting (which relied heavily on straight-to-video serial-killer-movie clichés), its plausibility or Larsson’s anti-authoritarian politics. They were smitten with that novel and its two sequels — “The Girl Who Played With Fire” and “The Girl Who Kicked the Hornet’s Nest” — because of the fierce charm of Salander and Blomkvist, and their unlikely chemistry. And because Larsson was so adroit at conjuring a moody, noirish Sweden that turned the stereotype of a clean, bright Scandinavia (where people drive Volvos and buy Ikea furniture) back into a land of long winters, haunted by the ghosts of Strindberg and Bergman.

In “Spider’s Web,” Mr. Lagercrantz demonstrates an instinctive feel for the world Larsson created and for his two unconventional gumshoes: Blomkvist, the dedicated, mensch-y reporter (and unlikely middle-aged girl-magnet); and Salander, the fierce, damaged girl who looks like an angry, punked-out version of Audrey Hepburn (if you can imagine Holly Golightly rocking tattoos and piercings, instead of a tiara) and who fights with the kick-ass video game skills of Lara Croft.