There has been no need for detection in Basle since the invention of the tracers, tiny motes in the air which can reveal the slightest illegality, but now the city has been hit by a spate of murders. Once again, Roberta Morgenstern and Clement Martineau are on the trail, caught up in the devil's dance. A new killer, bound to the will of the winds, is committing a series of terrible and violent crimes. Not only this, but the rain is incessant and water levels are rising. Soon the dams will be breached, and all Basle will be underwater. High speed chases across roof tops and through winding streets lead Roberta and Clement to the Queen of the Gypsies, the pirates of the lagoon, and finally to their fateful meeting with the deadly Baron of the Mists.

First published in France under the title 'Un Tango du Diable' by editions Albin Michel S.A in 2003.