It's finally go time. The guys that jump from the plane are Poulsson, Knut Haugland, Arne Kjelstrup, and Claus Helberg.
Once they're on the ground, Poulsson comes clean to the other guys about what their mission really is (they thought they were just going to train other resistance fighters). None of the other guys seem to have any problem with a drastic change in plans.
They have four weeks to scope out the plant, get info on the German guards, and check on the landing site for the British commandos to come in on.
When they wake up and figure out where they are, they realize the plane that dropped them made a huge—we're talking sixty-five mountainous miles huge—mistake. Now the four men need to haul six hundred pounds of weapons and supplies that were dropped with them over roughly seventy miles of snowy terrain. Awesome.
They make themselves into a relay of sorts and divide the gear into seventy-pound packs. They ski a set distance, put the pack down, and then ski back for their second pack and ski the trip again. Making things even worse, the weather has been so mild that the snow is wet and sticky, and the lakes they should've been able to go across aren't frozen enough, so they have to take the long way around. Talk about perseverance.
After three weeks of beyond-grueling physical trials, they finally make it to their destination, where they make soup out of dog food. Sweet victory.
Haugland radios to London that they're finally there and preparing to do their duty, but his fingers are so frozen that the people in London think they might be getting tricked by German agents (because his Morse code sounded different than usual). Luckily, he successfully answers a security question, and the mission is a go.
Ten days later, British commandos have taken off in their superlight wooden gliders, seventeen people to a plane. They are basically just attached to a Halifax bomber and dragged behind until they are ready to be released to glide to their destination.
As the pilots fly over the landing site, they have a hard time seeing the lights that Poulsson et. al. have set up.
One of the bomber pilots turns around to make another run over the target area, and the rope pulling the glider snaps. The glider slams into a mountain, killing eight men instantly. Four other have broken bones, and the other five get lucky with more minor injuries.
Two of the able-bodied survivors walk to a nearby farmhouse and ask the owner to call a doctor. The doctor agrees to come, but he alerts the Gestapo, too, who find all the evidence they need to realize that an attack at the Vemork plant is about to be attempted.
The Germans disobey all accepted rules of war in how they treat the survivors. They poison the four badly injured men and dump their bodies into the sea, while the other five are taken to concentration camps and interrogated (unsuccessfully, we should add) before being blindfolded and shot in the head.
Unfortunately, the second glider has a very similar story. It gets lost in the fog, crash-lands, and is quickly found by the Germans, who shoot the survivors on site.
To make matters even worse—especially for Poulsson, Haugland, Kjelstrup, and Helberg—the Germans are onto them, so they increased the number of guards around Vemork and started placing land mines around the plant.
Colonel Wilson contacts the Norwegian volunteers still training in Scotland and asks them to stand by for a "particularly dangerous enterprise."