As a pilot episode, "The Informer" dispenses with the formalities in classy fashion -- subtle yet memorable character introductions, plot outlines loosely yet accurately revealed, and tastes of those things to come given.
We are introduced to our band of Heroes as a bunch of World War II prisoners held captive by a hapless bunch of Germans. It is made known early on that Hogan and his boys control the camp along with its Kommandant and Sergeant of the guard. In the opening moments, a prisoner escapes and (wildly) another Allied escapee escapes into Camp 13.
Hogan and his men are running a prisoner processing center under the very nose of their jailers, Kommandant Wilhelm Klink and Sergeant Hans Schultz. Escaping prisoners from miles around are sent through Camp 13 to their ultimate destination of London.
Somewhere along the way, the "Krauts" (an accepted term for hated Nazis both during the War and when "Heroes" was filmed) decided to bury a spy in the system to flush out the escape and prisoner delivery service. This spy was sent to Camp 13.
Colonel Robert E. Hogan nearly immediately spots the fink by asking a series of simple questions about the rat's American unit. When Wagner (the fake) is unable to answer correctly, the troops are rallied to set up the poser's downfall.
Much is revealed about the prisoners' operation in this pilot episode. To see the scheming of Colonel Hogan, Sergeant Kinchloe, Sergeant Carter, Corporal Newkirk, and Corporal LeBeau at the hands of Colonel Klink, Sergeant Schultz, and the rest of the bad guys, please see this episode and start your voyage into World War II, Hogan style.