Now on the beach, the two principal actors in whatever drama was about to be performed, moved swiftly past the rock behind which Marc rested and raced purposefully to the left. This only lent further intrigue to the affair since such a course, if followed to it's ultimate end, could only lead them crashingly against a further wall of the cliff. And considering the rate at which the pair were traveling, such a collision seemed altogether probable ... even imminent. Eagerly, Marc jack-knifed forward to keep them in sight. * * * * * But about half way to the wall, the little man skidded to a disordered stop and pointed a chubby finger toward a large rock that jutted straight and tall from the sands, like a staunch sentinel standing guard. "That one'll do," she shrilled, and to Marc's bitter disappointment, disappeared behind the boulder's shielding bulk. The woman, still reluctant, paused at the rock's edge. "It won't work," she insisted. But her voice had now lost some of its authority. She followed her companion into the obscurity behind the rock. Marc would have given his immortal soul, along with his only copy of Forever Amber, to have known what it was that was not going to work behind that boulder. He felt meanly cheated. He felt that the intruders, like the waves, had led him to expect great things, then deliberately let him down. For a moment he knew what it was to be a trusting chorus girl who had been promised jewels, only to find, by the morning's depressing light, that she had received only a hangover and a pair of cheap stockings. He knew what it was to-- Then, suddenly, he only knew panic as a tremendous explosion grasped the little beach and shook it like a limp dishrag. Rocks, dislodged from the face of the cliff, began to fall everywhere through churning, sand-laden air. Marc wasn't bored any more. He clutched the rock at his side with all the zeal of an impassioned suitor back home after a three-year absence on a desert island. His attitude clearly intimated that he loved that rock dearly and nothing would ever part him from it. Something that was not a rock landed thuddingly at his side, but he was too distracted to notice. "Earthquake!" he gasped. [Illustration: The sudden, nerve-shattering blast turned the world upside down, and the woman along with it.]