I was curious what would happen if Stalin were captured by the Nazis, perhaps in the opening phase of Barbarossa.
This is perhaps not as unlikely as it would seem. Stalin refused to believe that Barbarossa was really happening, and suffered a mental breakdown with the thought of being arrested and executed for his failure on his mind.
So, perhaps in denial in the events and not in his right mind, Stalin visits the front--and get captured by advancing German forces. Perhaps unlikely, but I suspect plausible, given how resolved he was that there would be no war.
What do the Nazis do with Stalin in their hands? Were there any plans on what would be done in this situation? And how does this change the nature of the war on the Eastern Front?