Hogan and Co are out investigating a downed German rocket. Hogan cannot identify what type of rocket it is and wants to take it back to England for study. But it is too big for them to transport and it cannot be dismantled piecemeal. They cover it up until they decide how to deal with it, but Hogan is stuck for an idea.
Then Marya arrives in camp, accompanied by a scientist, Dr Otto Von Bornemann. Von Bornemann built the rocket. It is a V-3, and as this is the second time von Bornemann has lost it, Hitler is losing patience with him. They are looking for it and are pressing Hogan for information. Hogan does not have much choice, and his information leads the Nazis to the rocket, which is brought to Stalag 13. Marya tells Hogan that this was a ploy to put him in a position to steal the rocket. They can send the rocket by flying it, but Marya wants it to go to Moscow and Hogan wants London. Meanwhile, they steal the rocket with Marya's help, and hide it in their barracks. She she also warns Hogan that Major Hochstetter is coming.
When Von Bornemann and Klink discover what has happened, Marya misdirects their search to enable Hogan and Co move the rocket to the recreation hall. Hochstetter arrives, and Hogan tells him that he saw some men take the rocket through the fence. Upon examining the fence, Hochstetter moves his search outside the camp. Eventually Marya takes Von Bornemann and his assistants to the rec hall, where they find the rocket ready to fire. Hogan hints to Von Bornemann that he could be in serious trouble as this is the second time he has lost the V-3 because of a close association with a Russian agent, so Von Bornemann and his assistants accept his help in getting out of the country.
The question of whether the rocket goes to London or Moscow is decided by the toss of a coin: London. Von Bornemann is to go with the rocket, which is a manned rocket. But there is no ejection mechanism, which means Von Bornemann and his assistants have to fly it kamikaze. The rocket is launched, and London is on standby for the rocket and rescuing the men. Hogan tells Hochstetter that the scientists went on a suicide run in their own rocket. Hochstetter is not entirely convinced and warns Hogan that one day he will go too far.