The episode begins when an Allied aircraft loses power and had to land in a field. The airmen are brought to Stalag 13 where they are incarcerated.
Lt. Miller tells Hogan that they were able to land thanks to Captain Martin's actions. The entire crew owes their life to his quick emergency decisions. But when they find out that Captain Martin is in Klink's office, Hogan wants to listen in. What they learn is that Captain Martin is really Hans Strausser, an agent of Germany. He has some vital information that needs to be relayed to the German High Command. Strausser has plans of the next Allied offensive. He could have only got that information from someone leaking information from the Allied command. Hogan has to find out who, in the top Allied brass, is leaking the information to the Germans.
This episode held the viewer's attention from the beginning to the end. There was no time to get bored since we go from one scene to another- in order to get this entertaining tale completed before the time allotment ends. As we are half-way through the final season, things should be dropping off. But actually it seems the shows are getting better. This is one of those better shows.