The Nazis install gas pumps at Stalag 13. Hogan and Co find out it is to gas up convoys on their way to France. They figure Stalag 13 has been chosen as the gas station because the Allies will not bomb a POW camp. Hogan orders Kinch to contact the Underground for any information. The Underground replies that they are to meet 'Eskimo' at the Hofbrau for information on the first convoy.
Le Beau points out that Klink is overdue for a surprise inspection, which could interfere with the rendezvous. Therefore Hogan and Co trick Klink into springing one so Hogan will be clear to meet Eskimo. Eskimo tells Hogan that the first convoy will arrive the following week, and if the gas station is established, this will reduce its travel time to France. Orders are to destroy the pumps. However, gas storage is stockpiling at Barracks 12 and Klink will not remove the inmates in Barracks 12 in order to forestall any sabotage. Realising it is too dangerous to destroy the pumps, Hogan decides to destroy the convoy instead.
After working out a plan with the aid of a model of the camp, gas pumps and convoy, and meeting Eskimo again for more explosives, they are ready. When the convoy arrives to fill up, Kinch, Carter and Le Beau sneak out to plant explosives underneath the vehicles. Newkirk joins the extra security disguised as a guard in order to act as a lookout and throw off any prying Germans. The convoy is destroyed.
Klink tells Hogan that the Gestapo have realised it was sabotage and are investigating. But he has received orders to dismantle the pumps.