Henri Roubier is an industrialist who has negotiated a contract to build a national roadway, making himself a rich man in the process. On his way to a meeting with the French Prime Minister, he gets caught up in a traffic jam and two hitch-hikers force their way into his car – a young man and a young woman, who have just met. Roubier drives off at great speed – but his car goes over the edge of a cliff. When the three regain consciousness, they discover that they are in car which is perched precariously on a tree growing out of the cliff face. Below, is a fall of several hundred feet...