Four prison inmates have been hatching a plan to literally dig out of jail when another prisoner, Claude Gaspard, is moved into their cell. They take a risk and share their plan with the newcomer. Over the course of three days, the prisoners and friends break through the concrete floor using a bed post and begin to make their way through the sewer system – yet their escape is anything but assured.

Cast: Michel Constantin, Jean Keraudy, Philippe Leroy, Raymond Meunier, Marc Michel, Jean-Paul Coquelin