Professor Marrot obtains the secret documents containing evidence of the illegal weapon transactions between the French government, in the face of its high official Leroi, and two African countries. Before making the public statement, Marrot finds himself under surveillance. In the critical circumstances his Italian friend and partner Angela takes action and the game continues.

An engineer has discovered a new special alloy for the construction of submarines and is about to launch it on the world market. To force him to give up the formula, his opponents kidnap his son.