Hogan and Co find something is interfering with their radio signals. Baker realises a radio detection unit has detected their signal and shuts down the radio. He does not think they have been traced. The message they did get is double red (urgent): the Underground has intelligence that must be radioed to Air Intelligence that night, and they are given a rendezous to meet a contact, Hercules. Hogan plans to commandeer Klink's car (by rigging brake failure) to meet him, and strings Klink along with ideas about meeting a rich young widow. Unfortunately, the lack of brakes causes the car to crash.
Things get even worse when Major Hochstetter arrives with news that they have picked up a radio transmitter in the camp. This means Hogan and Co now have to contend with radio detectors. Hogan's solution is to quickly repair Klink's car and take the radio transmitter with them - as the car radio.
Meanwhile, Hochstetter is setting up heavily armed radio detector units. His plan is to have volunteers make a frontal attack on the transmission signal and then his men will move in. Klink is horrified when he hears that he and his guards are to make the frontal attack, and tells Hochstetter that he will be out of camp on business (with his rich young widow). He orders his car to be ready by 6pm or he will have Hogan shot. Eventually, Hochstetter tells Klink that his men are cowards as they all seem to be on night duty and are so sorry they cannot volunteer. He will do the job without Klink's volunteers.
The car is ready to go, radio and all. But when Newkirk lets it slip about the transmitter, Klink panics because it could get him killed by Hochstetter's units. He orders Hogan and Co to clear themselves and the car out. They do themselves and the car up to look Gestapo and go to their rendezvous. Hercules passes them the information and they take him to one of Hochstetter's detector units as their 'prisoner'. They ask the goons to temporarily shut down the unit, saying they need to radio Gestapo headquarters, and transmit Hercules' information to Air Intelligence.
Hogan is surprised when Klink really does hit it off with a rich young widow. Klink's reward for Hogan is two bottles of champagne.