Knut Haukelid is met by two British officers when he arrives in London and is taken to an officer with the S.O.E.—Special Operations Executive, a secret British organization tasked with carrying out acts of sabotage behind enemy lines. They ask Haukelid if he'd like to work with them, and he's like, "Dude, when do I start?"
The S.O.E send Haukelid to Special Training School No. 3, a place Germans have heard about and dubbed "International Gangster School." There he meets about thirty Norwegian men who share his dream of going home and liberating their country from the Germans.
At the school, they are taught how to care for and utilize weapons, pick locks, crack safes, set booby traps, and use poison. They are taught how to kill with their bare hands. In other words, Haukelid is now Jason Bourne.
Next they send Haukelid to Scotland for parachute school in order to train for his covert re-entry into Norway.
The S.O.E picks five of the best men for a special mission. Of course Haukelid is part of the team—well, until an injury pulls him from the action. (What happens? He trips with a loaded weapon and shoots himself in the foot. This is not a Jason Bourne move, Knut; get your stuff together.)
Jens Poulsson is the leader of the elite team, and he's the only one fully briefed on their mission, which is to destroy the Vemork power plant built into the side of a mountain in Poulsson's hometown of Rjukan, Norway.
Apparently, Vemork is a vital target because it's the only plant in the world capable of producing large quantities of "heavy water," which is a key ingredient in the German atomic bomb program.
The plan is for the team to parachute onto a plateau in the wilderness near Vemork, scout the area, and set up a rudimentary landing strip on a frozen lake for thirty-four British commandos to fly in on gliders. Then they'll all set out to destroy the plant.