Into Thin Air by Carolyn Keene

his mouth.
    â€œSo what next?”
    She motioned him to follow her to thekitchen. Hannah Gruen, the Drews’ housekeeper, was just putting away the breakfast dishes.
    â€œI have some things to do in the garden,” said Hannah after Nancy had introduced Mark to her. “I’ll leave you two alone to talk.”
    After Hannah had left, Nancy got glasses out of the cupboard and set them on the counter. Mark sat on a stool. She poured them each a glass of juice.
    â€œFirst,” she began, finally addressing Mark’s question, “we go over everything that’s happened. Then we decide on a plan of action.”
    Nancy questioned Mark for more than an hour, going over all the details of the case from beginning to end. Although Mark mentioned a few minor details she hadn’t heard before, Nancy felt stymied when they had finished.
    Mark was staring at her expectantly.
    Nancy laughed. “You think I’m just going to come out with the solution, don’t you?”
    Now it was Mark’s turn to laugh. “Yes,” he said. “And I expect it to be brilliant, Detective Drew.”
    â€œWell, I’m sorry to disappoint you, but I’m afraid we’re both going to have to mull things over for a while,” Nancy told him. “What I’d like to do is go downtown. I want you to show me where you thought you saw Johnson.”
    â€œNo problem,” Mark said eagerly.
    Twenty minutes later they were in the shopping district. Mark led her to the street where he had taken the blurry instant photograph.
    â€œI don’t really see what we’re going to find out,” he said. “I saw him almost a week ago.”
    â€œYou never know,” Nancy replied in a tone that was deliberately mysterious. She grinned and added, “Seriously, it will help me get a feel for what happened that day.”
    Mark came to a stop on the sidewalk and pointed in different directions. “Here’s the jewelry store, there’s the camera shop. That means I was here and he was over there.”
    Mark stood Nancy in one spot and flung himself ahead of some shoppers to demonstrate Johnson’s position.
    â€œOkay,” Nancy noted. “Then where did he go?”
    â€œI told you. He bolted,” Mark said. He pointed up the street. “That way.”
    â€œAnd you went after him?”
    â€œRight. Until he dashed across the railroad tracks and the train came.”
    â€œLet’s do it,” Nancy suggested. “Exactly what Johnson did.”
    â€œSure.” Mark sprang into action. Together, they dodged a slow-moving group of shoppers and sped toward the railroad tracks.
    When they got to the tracks, Mark stopped. “The train came, and that was it. I was stuck here, where we are now. The whole thingdidn’t take more than two minutes.” He looked at her. “So?”
    â€œHmmm,” Nancy murmured, deep in thought. Then she looked up at Mark. “How fast was the train coming?”
    Mark shrugged. “Fast. It looked as if he had to jump to clear it.”
    Nancy backed up and took a running start. As she reached the open railroad barrier, she imagined an enormous train engine hurtling toward her, and she leaped across the tracks.
    As she did, her sunglasses bounced off her face. She kept going until she was clear of the tracks on the other side. Mark approached, walking at a more leisurely pace.
    â€œThat was it,” he called. “Exactly.”
    Nancy pondered what they had just done, glancing all around them. The street ran into a residential neighborhood of seedy tenement buildings. The man could have gone down any street, into any building. She hated to tell Mark, but it seemed as if their efforts had been useless.
    â€œWhat now?” Mark asked, waiting for more instructions from Nancy.
    â€œNow I’m going to get my sunglasses,” she said. “They fell off when I jumped across the tracks.”
    Mark