Prisoners in a French prison plot an elaborate escape by digging a tunnel. Apparently French prisons are nothing like American prisons, with inmates allowed to dress in street clothes and receive parcels containing pate, caviar, and pudding. The tunnel scenes are well constructed and are probably the best thing about this otherwise talky and lethargically paced film that feels much longer than its running time. There are extended scenes showing prisoners hammering through concrete and cutting through steel bars. And the cells are so sound-proof that guards just outside the door don't hear any of the loud hammering. The ending is ambiguous and unsatisfying.
