said. âBut why would somebody like him be off-roading in the desert?â
âMaybe for his research,â Frank said. âOr maybe heâs involved with the cactus thieves. Somehow he doesnât seem like the type to get his hands dirty transplanting big plants.â
âNo,â Joe said, âbut he could be the mastermind behind the rustling. He sure did act upset when we saw that thing under his truck.â
âHey, weâre pretty good, arenât we?â Frank said. âSo far weâve turned up three suspectsâKidwell, Perez, and the profâand we havenât even been here twelve hours.â
âAnd in those twelve hours, I havenât eaten abite,â Fenton said, âAre you interested in salvaging those gourmet hot dogs you left on the grill, Joe?â
âOh, my gosh!â Joe said, jumping for the door. âI forgot the dude dogs!â
âHold it!â Fenton called. âTheyâre in the fridge. I brought them in when they were done and you still werenât back. I rescued the beans, too.â
After wolfing down a late dinner, Joe began to feel drowsy. The fresh desert air was making him pleasantly tired, and he climbed gratefully into his sleeping bag on his bunk. Drifting off, he could hear the sounds that Grish had promisedâthe high-pitched songs of the coyotes, calling from one direction and being answered from another, under the stars in the chilly night air. He smiled and fell asleep.
He was awakened about one oâclock by a distant sound he couldnât identify at first. Listening for a few more moments, he realized he was hearing the revving of a big engine, like that of a slow-moving truck. The sound was coming from the west, though, not from the direction of the highway.
He got up and tapped Frankâs shoulder. âListen,â he whispered. âWhat does that sound like to you?â
Frank rubbed his eyes and listened. âEngines,â he whispered back. âOnlyââhe sat upââfrom the wrong direction.â
âExactly,â Joe whispered. âThe highway through the park is to the east of us. A vehicle on that highway would be moving fast, and the soundwould fade away. What weâre hearing is steady, like a vehicle sitting in one place with the engine running.â
âLike a truck running a winch,â Frank whispered.
âMaybe,â Joe whispered, glancing over to see if their father was stirring. âIt could be the cactus thieves.â
âLetâs check it out,â Frank whispered.
They pulled on their jeans, sweatshirts, and hiking boots, and tiptoed out the door. But as they started across the campground, Frank had an after-thought. âLetâs wake up Dad to tell him where weâre going,â he said. âWe can turn on the CB radio and take the walkie-talkie from the car. Then if we get out there and actually catch the thieves in the act, we can radio back to Dad, and he can get hold of Grish.â
âGood idea,â Joe said. They woke Fenton, explained what they were up to, and turned on the radio in the motor home. Grabbing the CB walkie-talkie from the car, they started hiking across the desert in the direction of the vehicle sounds.
The terrain was uneven and the footing a little tricky, even in the bright moonlight. Other than the engine noise the night was quiet, so they were able to head straight for the sounds. But after a while it seemed as if they werenât getting any closer.
Frank stopped. âYou know what?â he said. âI canât hear the engines anymore.â
Joe stopped to listen. âMe neither,â he said.âMaybe they shut down for a few minutes. Think we should keep going?â
âI donât know,â Frank said. He looked around at the moonlit desert landscape. With no city lights in the background, the stars were brilliant against the black sky. The nocturnal animals