Chemist Robin Gaunt believes he’s discovered the key to lasting world peace—in the form of the horrific poison gas he’s just perfected. Gaunt is certain that once the British government has the formula, no nation will ever dare start a war, for fear of the consequences. But Gaunt vanishes before can turn over the formula, and people start turning up dead—victims of some unknown poison.

It doesn’t take long for Bulldog Drummond to be on the case—and it doesn’t take long for him to realize that the man behind the kidnapping and murders is his arch enemy Carl Peterson. This leads to a final confrontation worthy of a Bond movie, as the hero and the evil genius face off in a giant zeppelin loaded with deadly toxin.