Moon Mirror by Andre Norton

they went on Memorial Day with flowers for Grandma and Grandpa Targ. It was different because it never said “dead” but “disappeared.”
    Rick had been excited, said it sounded like a mystery. He had begun to ask around, but none of the neighbors knew anything—except this had all once been a farm. Almost all the houses on the street were built on that land. They had the oldest house of all. Dad said it had once been the farm house, only people had changed it and added parts like bathrooms.
    Lizzy and Matt—
    Rick had gone to the library and asked questions, too. Miss Adams, she got interested when Rick kept on wanting to know what this was like a hundred years ago (though of course he did not mention the stone, that was their own secret, somehow from the first they knew they must keep quiet about that). Miss Adams had shown Rick how they kept the old newspapers on film tapes. And when he did his big project for social studies, he had chosen the farm'shistory, which gave him a good chance to use those films to look things up.
    That was how he learned all there was to know about Lizzy and Matt. There had been a lot in the old paper about them. Lizzy Mendal, Matthew Mendal, aged eleven and five—Lesley could almost repeat it word for word she had read Rick's copied notes so often. They had been walking across this field, carrying lunch to their father who was ploughing. He had been standing by a fence talking to Doctor Levi Morris who was driving by. They had both looked up to see Lizzy and Matthew coming and had waved to them. Lizzy waved back and then—she and Matthew—they were just gone! Right out of the middle of an open field they were gone!
    Mr. Mendal and the Doctor, they had been so surprised they couldn't believe their eyes, but they had hunted and hunted. And the men from other farms had come to hunt too. But no one ever saw the children again.
    Only about a year later, Mrs. Mendal (she had kept coming to stand here in the field, always hoping, Lesley guessed, they might come back as they had gone) came running home all excited to say she heard Mart's voice, and he had been calling “Ma! Ma!”.
    She got Mr. Mendal to go back with her. And he heard it too, when he listened, but it was very faint. Just like someone a long way off calling “Ma!”. Then it was gone and they never heard it again.

    It was all in the papers Rick found, the story of how they hunted for the children and later on about Mrs. Mendal hearing Matt. But nobody ever was able to explain what had happened.
    So all that was left was the stone and a big mystery. Rick started hunting around in the library, even after he finished his report, and found a book with other stories about people who disappeared. It was written by a man named Charles Fort. Some of it had been hard reading, but Rick and Lesley had both found the parts which were like what happened to Lizzy and Matt. And in all those other disappearances there had been no answers to what had happened, and nobody came back.
    Until Lizzy and Matt. But suppose she and Rick and Alex told people now, would any believe them? And what good would it do, anyway? Unless Lizzy was right and people should know so they would not be caught. Suppose someone built a house right over where the stone stood, and suppose some day a little boy like Alex, or a girl like Lesley, or even a mom or dad, disappeared? She and Rick, maybe they ought to talk and keep on talking until someone believed them, believed them enough to make sure such a house was never going to be built, and this place was made safe.
    “Matt—he kept sayin’ he wanted his mom,” Alex's voice cut through her thoughts. “Rick, where was his mom that she lost him that way?”

    Rick, for the first time, looked helpless. How could you make Alex understand?
    Lesley stood up. She still felt quite shaky and a little sick from the left-over part of her fright. But the worst was past now, she had to be as tough as Rick or he'd say that was