While retaking Europe an allied soldier finds a book with invaluable secrets that lead him on a worldwide treasure hunt where powerful opponents will stop at nothing to have it all for themselves.

Examples:
“When reclaiming the Nazi Camelot during WWII”
“an allied soldier sets out on a worldwide treasure hunt”
“an allied soldier finds himself up against a megalomaniac US general”
“following clues from a looted ancient Dead Sea copper scroll”
Baddie's goal: Nazis need the treasure to birth the Fourth Reich.

This is your story, make these yours; hope you find these examples helpful.