Johan Falk, a Norwegian undercover cop and a civilian infiltrator penetrate one of Göteborg's toughest criminal gangs. When a new player enters the game and wants armor-piercing grenades, the SSI suspects that someone is planning to start a gang war.

During a seizure of Estonian amphetamines, the SSI realizes that they're dealing with the legendary Russian mafia boss "Mr. K." Johan's undercover man infiltrates Europe's most dangerous crime syndicate, formed of ex-KGB officers.

A violent war in the restaurant business has flared up, and when Johan Falk learns that one of the restaurants is run by Leo Gaut, a gangster he put behind bars years ago, he unwittingly triggers a series of cold-blooded acts of vengeance.

The SSI is to clamp down on the smuggling of young Eastern European women to work as prostitutes in Gothenburg. But Johan Falk's infiltrator, the young Polish woman Hanna, takes her assignment further than anyone expected...

When a prosecutor pursuing the most dangerous motorcycle gang in the country is killed in a bombing, the police high command orders the SSI to use every means to combat them. It becomes clear that something has gone terribly wrong within the police.