The story alternates between the activities of a gang that cracks safes with oxyacetylene torches and the police, who are always one caper behind them. The gang's operations are reminiscent of the spellbinding movie Rififi -- tightly scheduled and divided among specialists. Chief Inspector Martineau deploys his men for a frustrating wait. He knows that the break will come when gang members wear out each other's nerves. When it happens the police are ready and the reader has been given a front row seat overlooking the aristocracy in a sub-culture of crime.