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.
Michel Constantin
as Geo Cassine
Jean Keraudy
as Roland Darban
Philippe Leroy
as Manu Borelli
Raymond Meunier
as Vossellin / Monseigneur
Marc Michel
as Claude Gaspard
Jean-Paul Coquelin
as Le lieutenant Grinval
André Bervil
as Le directeur de la prison
Eddy Rasimi
as Bouboule
Philippe Dumat
as Un gardien
Albert Augier
as Un gardien
Jean Becker
as Un gardien
Raymond Bour
as Un gardien
