Unique concept, Stephen Czerwinski. I like the logline, but I think it needs to be tightened up a little.

Here’s a logline suggestion: “As the world recovers from the horrors of WW2, the U.S. recruits a secret military expedition with one goal: find a Nazi lab in the Antarctic wastes that’s bent on awakening an ancient evil that will plunge the planet back into darkness.”

Since the military expedition will be searching for the lab, we can assume it’s hidden, so you could remove “hidden.”