In order to find the intel which Borisov passed on to Norling before his death, Hamilton travels to Ukraine, unknowing that Haig has hired assassins for the same goal. Haig turns out to be working for Pence, who convinces Gripenberg into buying his cybersecurity-system after the latest cyberattacks. After a visit from SÄPO, DG decides to return into the battlefield. Hamilton succeeds in finding Norling's USB-drive which had been hidden by Mike.

During a top-secret NATO operation in the Mediterranean, a Swedish attack diver is murdered. Hamilton knows the victim from his time as a Navy SEAL and travels to Toulon's military base in the south of France to investigate the incident.

Hamilton and Kristin go undercover to get more information about the background to the murder. A dangerous hunt, which ultimately affects the whole world, leads via the Riviera's casino to exclusive villas and out to the Mediterranean.