Many of the plots in "12 O'Clock High" are pretty unrealistic for a B-17 crew. For example, the bomber group seems to be all over the place....bombing France, Germany and flying missions to North Africa and Yugoslavia! And in this one, they fly across Europe to Russia!! This is a huge goof, as the chances of a B-17 successfully traversing Europe both ways would be negligible! Plus they just didn't fly missions like this....a transport craft (such as a C-46 or C-47) would have done the job...not a bomber. But, I can forgive some of this, as how could they fill three seasons of episodes unless they mixed it up a bit and tried some unusual plots.
When the story begins, Colonel Gallagher and his crew are flying around the Axis/Russian border. Their job is to transport two generals and back to England. Not surprisingly, the plane is attacked and damaged...and some of the crew and one of the generals are forced to bail out...and a few remain with the injured general and try to land the plane. After landing, they are caught in a battlefield...with Germans and Russians around them. Their goal is to get rescued by the Russian allies instead of getting shot by the Germans.
The episode is tense and exciting...so much so you can look past how contrived the plot is. Plus, it is very satisfying seeing the sergeant killed near the end....see the show and you'll see what I mean!