It's a beautiful day in Slottsskogen, Gothenburg's idyllic city park, when suddenly the unthinkable happens gunfire amidst innocent people. Two gangsters begin shooting against each other and a large police operation starts. The conflict grows rapidly to involve several gangs from Gothenburg underworld. GSI goes into action to try to identify a new player which proves to be both larger and better armed than any other. The only clue is a tattoo on one of the killed gang members, and the plot thickens when it turns out that the same tattoo worn by Rydell's new gang.