No sooner had it moved past, than it abruptly sped up and drove off. As it did, Marten caught sight of the driver. A chill touched his neck and ran down his spine. It was the same man who had been driving the car that had so slowly passed him near the Washington Monument the night before.

What the hell is this? Marten thought. Coincidence? Maybe. But if it's not, then what is it? And what does he want with Dr. Stephenson?

• 8:32 P.M.

Marten saw a car turn at the end of the block and start down the street toward him. As it neared he could see it was a taxi. Like the other car it slowed as it reached Stephenson's home, then it stopped. A moment later the rear door opened and Dr. Stephenson got out. She closed the door and the taxi drove off, then she started for the house. At the same time Marten stepped from his rental car.

"Dr. Stephenson," he called out.

She started and looked back.

"It's Nicholas Marten, Caroline Parsons's friend," he said. "I'd like a few minutes of your time."

Stephenson stared at him for the briefest moment then suddenly turned and walked hurriedly down the sidewalk away from her house.

"Dr. Stephenson!" Marten called again and went after her.

His feet touched the far curb and he saw her glance back. Her eyes were wide and filled with fear.

"I mean you no harm," he said loudly. "Please, just a moment of your-"

She turned back and kept on. Marten followed. Suddenly she broke into a run. So did Marten. He saw her pass under a streetlight and then disappear in darkness beyond. He ran faster. In a moment he was under the streetlight and then in the darkness. He didn't see her. Where the hell was she? Another twenty feet and he had his answer, she was standing there watching him come. He stopped.