Foreign spies steal the formula for a revolutionary explosive created by an Italian scientist and to decrypt the secret code they kidnap his secretary who knows about it.

A wardrobe mistress at a Vienna theatre wins a competition, receiving as her prize a luxury tour round Italy. On the train she meets an impoverished young Italian who pretends to be a prince.

A story of the Second Punic Wars, beginning with Scipio's futile pleas to the Roman Senate to build an army to battle Hannibal, that climaxes with the battle of Zama.