Free Caught (Missing) by Margaret Peterson Haddix

seats.
    “If no one gets on in the middle of the night,” Jonah whispered back.
    He’d thought their voices were quiet enough to get lost in the rumbling of the train wheels against the rails. But Mileva jerked to alertness suddenly and narrowed her eyes, peering right in their direction. Jonah might have expected her to be hysterically afraid—after all, she’d been sobbing moments before. But she only sat calmly, her head cocked to the side. Listening. Watching.
    “You’re still with me,” she said after a few seconds. “You’ve followed me all the way from Bern. And now we’re alone. You can talk to me. Who are you? Where are you from? What are you doing here?”
    Jonah and Katherine stood frozen. Jonah was afraid that if he even took a breath, Mileva would be able to hear him.
    “I know you’re there,” Mileva said. “Albert, my husband, he’s an incredible scientist because he’s so good at thinking. The ideas that come out of his head! He’s a genius, you know? Someday the whole world is going to know it.”
    Mileva waited only a second to see if they would respond. Then she went on.
    “But Albert could walk through a blizzard and not know it was snowing. He was terrible at observations with lab experiments—he never would have gotten through university if the rest of us hadn’t helped him,” she said. She shifted slightly in her seat. “But me—I’m good at observation. All day today I’ve been watching the doors that stay open a moment too long, because you’re walking through them. I’ve seen the food disappear off tables in train-station restaurants.”
    Katherine looked at Jonah and frowned.
    Hey! We had to eat! he thought fiercely in her direction.
    She only scowled.
    Silently.
    Mileva kept listing all the ways they’d failed to be completely invisible, completely unnoticeable.
    “I’ve felt my train seat move like someone was climbing on top of it,” she said. “I saw mud that you must have left behind. I’ve smelled your . . . was it perspiration? Ordinary old human sweat?”
    Jonah began surreptitiously sniffing his underarms until he saw that Katherine was glaring even harder at him and making chopping motions with her hands to say, Stop it! Just—stop!
    He glared back at her, hoping she was getting the message: I couldn’t help it! I’m a teenage boy! It was hot! Excuse me if I didn’t think to bring deodorant with me when we got zapped back in time!
    Jonah looked back at Mileva and saw that while he and Katherine had been holding their glaring match, Mileva had slipped her papers back into her bag and pulled out the compass instead. She was holding it up in the air, turning it over and over, examining it. She clicked it open and shut, again and again.
    “Can spirits get muddy and smell like sweat?” Mileva asked. “Do they carry compasses? Is this really a compass?”
    The way she was holding it just with her fingertips, Jonah realized he could lunge at her and grab it away from her in an instant. He braced himself up on his toes, readyto dive—and in the next second Mileva was clutching the Elucidator with both hands again, holding it tightly against her skirt.
    She’d realized the possibilities too.
    “The people I grew up with were so superstitious,” she said. “They put brooms upside down outside their bedroom doors to sweep away nightmares. They believed beeswax was sacred. They would only want to know what kind of spirits you are—evil or good? Do you mean me harm or benefit?”
    Jonah looked at Katherine. Back in the 1480s, on their first trips through time, they’d talked to people from that era: monks, the king of England . . . But they’d been so ignorant then—they’d just been lucky that their conversations hadn’t caused serious damage to time.
    Katherine was shaking her head at Jonah even as he was shaking his head at her. They were agreeing: Neither one of them would answer Mileva’s questions.
    “The people I met at school—my