Frankfurt, May 1937. The Hindenburg, the world's largest airship, is getting ready to fly to New York. A vehicle of staggering dimensions, it is the pride of Nazi Germany. But it has one serious flaw: due to an American embargo preventing the sale of helium to Germany, the Hindenburg is filled with highly combustible hydrogen gas instead. To Merten Kröger, an engineer who helped design the Hindenburg, the ship is a stick of dynamite waiting for a spark.
The young man of great charm but modest means has fallen in love with the wealthy Jennifer van Zandt, the daughter of an American industrialist who wants to sell helium to the Germans. Just before the ship takes off, Merten learns how far the industrialist will go: he has had a bomb placed on the airship. What van Zandt didn't know is that his wife and daughter would be on board. Merten sneaks aboard the airship without a minute to spare.