The water-skier’s curving white wake mirrored a vapor trail in the azure sky above the Riviera. The bronzed man on a single ski swept into a final slalom before the speedboat towing him slowed down between the line of buoys leading to the jetty. The skier leaned back against the pull of the rope and the roar of the engine faded to a hum three markers out from the jetty. Two... one...

Suddenly an explosion lifted the surface of the sea.

When the tower of white water collapsed into the ocean, the speedboat, the two young men crewing it and the skier had all vanished.

There was pandemonium among sunbathers lying on the hot sand. A crowd had gathered along the railing of the palm-fringed promenade, excited voices rising above the chaos on the beach.

Farther along the promenade a man in a white sharkskin suit sat alone in a parked Mercedes. He slid a small detonating device into the glove compartment, then started the car. As he pulled out into traffic and headed for Cannes, he was smiling.

One hour later, a red and silver executive Jet began its descent toward the auxiliary runway on the seaward side of Nice International Airport. Circling over the blue crescent of the Baie des Anges, the pilot saw what seemed to be some kind of disturbance on one of the beaches. He could make out the red cross on an ambulance roof, and flashing amber roof lights of patrol cars. Traffic on the promenade was jammed as far as the Airport entrance.

The pilot dismissed it and concentrated on his descent. He turned to the expensively dressed man behind him. “Fasten your seatbelt, Mr. Ralfini. We’re ready to touch down.”

The owner of the jet nodded and snapped the belt’s safety clasp together. “Make it a smooth one, Joe,” he said.

The controller’s voice in the pilot’s earphones crackled last minute approach instructions. The pilot checked out the battery of lights on the instrument panel. Satisfied, he banked the aircraft and pointed the nose down. The long streak of runway rushed toward them.