Fredrika Bergman gets assigned to the investigation of a hijacked plane, whose co-pilot, Erik, turns out to be the son of her former boss, the legendary police investigator Alex Recht.

Alex convinces his son to turn around the airplane without Karim's knowledge; Fredrika meets detained professor Said Khelifi, whose release from custody is one of the hijackers' demands.

Despite his earlier suspicions, Erik asks passenger and aircraft technician Osman to help him; Fredrika's doubts about Said Khelifi's guilt intensify as the events surrounding his arrest seem increasingly strange.

Erik and Osman desperately try to get into the cockpit without the passengers noticing their distress; Captain Karim Sassi becomes the prime suspect; Alex tries to locate his family; Fredrika's parallel investigation takes increasingly strange turns.

Lydia holds Karim hostage and Alex fails in his attempts to talk her out of it; Fredrika discovers that Adam had two siblings.