"Time-lapse cameras," Ned replied.

"They're set to take exposures every fifteen minutes. They even record the date and time at the bottom of each negative."

"Incredible," Nancy said, then pointed to the hut. "Is that where Brad was hurt?"

"Yeah," Ned replied. "We keep a few snacks and drinks in there. Apparently, Brad was heating water for coffee. When boom! I heard the explosion and ran up the hill. Brad was lying across the doorstep, unconscious."

Nancy shook her head sympathetically.

"The force of the explosion must have blown him out the door. He's lucky he wasn't killed."

Inside the hut were two chairs and a folding table covered with computer printouts and camera gear. Several bags of food pellets and a stack of traps lined the far wall. Above it was a shelf with a canister of sugar, instant coffee, and tea bags.

Nancy pointed to a blackened object in the comer of the room. "Is that the stove that blew up?"

Ned nodded, and she went over to it. The stove consisted of one burner attached by a copper tube to a canister of propane. Nancy checked the propane tank. The fitting between it and the tubing was tight, but when she traced a path up the tubing to the nut that connected it to the burner, she let out a gasp.

"Find something?" Ned asked.

Nancy held the tubing and the bolt up to the light. "Look at this," she said. "See those scratch marks? Someone's tampered with the nut,"

Ned's eyes narrowed. "That means when Brad turned on the stove, propane started escaping."

"Exactly," Nancy agreed. "And when he lit the match, there was an explosion."

Ned straighted up. "So it wasn't an accident.

Someone deliberately tried to hurt Brad!"

Chapter Three.

Or kill him," Nancy added as she de- tached the tube and put it in the pocket of her jacket. "This is our first piece of evidence."

From the doorway, someone spoke up.

"What's going on here?"

Nancy turned and saw a lanky man of about fifty, whose black hair was sprinkled with gray at the temples. He had a deeply tanned face and a wide, unsmiling mouth. A tall, dark, good-looking guy in a ranger uniform and a young woman clad in blue jeans and a purple Emerson College sweatshirt stood just behind him.

Ned moved toward the group. "I was just showing my friend Nancy around. Professor Trainey, this is Nancy Drew." He gestured to the two people behind Trainey and added, "That's Jack Billings, a park ranger, and Alicia Nivel, from Emerson."

"Hi. You're Ned's girlfriend from River Heights, aren't you?" A brief smile flashed across Alicia's face. "He talks about you a lot."

For a minute no one said anything. Then the professor turned to Ned. "Did anything new turn up on the computer?" he asked.

Ned ran his hand back through his hair nervously. "Umm-I didn't get a chance to look. Nancy showed up just when I got to the command post," he explained.

"I see," Trainey replied. He crossed his arms at his waist and stared at Ned. "We've got fifty marmots missing, final observations to make before we leave on Sat.u.r.day, at least a day of packing ahead of us-and you've invited a visitor here. I must say, your timing surprises me."

Ned swallowed. "But, sir, Nancy is-"

Trainey held up his hand. "I need you down at camp in ten minutes to draft a plot of today's readings." He turned and headed down the path.

Alicia gave Nancy an apologetic smile and said, "You'll have to forgive us. We're all pretty tense these days, what with the marmots miss- ing and the grant extension hanging in the balance."

The ranger patted her on the back and said, "Don't worry, Alicia. You'll make it."

"Thanks, Jack," Alicia replied.

Ned shook his head despondently. "I just wish Trainey had given me a chance to explain why I invited Nancy. She's a well-known de- tective and is going to track down the poach- ers."

Nancy would have preferred to keep her role a secret for a little while longer. Oh, well, too late now, she thought.

Jack gave Nancy a big smile. "A private eye," he said. "Well, I'll be. And a pretty one, too."

Nancy tried to keep from blushing, but it was no use. She thought that Jack was amaz- ingly handsome-rugged and intelligent look- ing, too. She turned to Alicia and asked, "What did you mean about the grant exten- sion?"

"Our study is being paid for by a federal grant," Alicia said. "But there were cost over- runs, so Professor Trainey applied for an ex- tension, but in the meantime he's been paying some of the expenses out of his own pocket."

Nancy whistled. "That's pretty daring of him," she said. "Is he wealthy?"

"I doubt it," Ned said. "He lives in a small cottage off campus and drives a beat-up truck.

His work is about the only thing that seems to matter to him."

Nancy turned to Jack. "I met a couple of park maintenance men today named Richard and Piker. Do you know them?"

Jack hitched his thumbs in his belt and said, "Yes, I do. Why?"

"They weren't exactly friendly when I met them at the campsite a little while ago," Nancy replied.

Jack gazed at Nancy. "I'm sorry if they gave you a hard time. I told them about what happened to Brad and asked them to be on the lookout for trouble. Actually, Piker and Rich- ard are really good guys," Jack went on.

"They're just better at building walkways than relating to the public."

"Oh," Nancy said, keeping her doubts to herself. "Ned told me about Brad's accident.

That was the day before yesterday at about eight in the evening, right?"

"Seven fifty-three, to be exact," Ned said.

Nancy flashed him a grateful smile and continued. "Were either of you around when it happened?"

Jack gave a vigorous shake of his head. "Not me. I was at the ranger station, giving a talk on the mammals of Yellowstone. It started at seven."

"That's right," Alicia said. "Jennifer and I were there. The slides were terrific!"

"Did either of you happen to use the stove that afternoon?" Nancy asked, her eyes casu- ally moving from Jack to Alicia and back.

Alicia frowned in concentration. "I think I did. When I came up to change the film in the cameras, I made some hot chocolate."

"What time was that?" Nancy pressed.

"Six-thirty," Alicia replied. "I left about ten minutes later to go to the lecture. I made it just in time."

"I remember you huffing and puffing as you ran into the room," Jack said with a grin. "But speaking of time, Trainey told us to meet him in ten minutes."

"And me in the doghouse already!" Ned exclaimed. "Come on. Nancy."

Nancy and Ned jogged down the path to the campsite with Alicia and Jack close behind them. When they reached the parking area, Ned gave Nancy a quick kiss, then dashed off.

Nancy drove away, thinking about the inves- tigation. If Alicia's recollection was correct, the propane stove was working at six-thirty on the day of the accident. But by seven fifty- three, it had been sabotaged. If she could place someone at the observation hut during that time period, it would go a long way toward breaking the case.

As she drove up to the hotel, she saw Bess standing on the porch, peering anxiously at the road. The moment she spotted Nancy, she started waving wildly. Nancy parked and ran over to her.

"What is it, Bess?" she demanded. "What's wrong?"

"Nothing's wrong," Bess replied. "I think I just solved the whole case!"

"What do you mean?" Nancy sank down onto a porch swing.

Bess dropped down next to Nancy and handed her a piece of paper. "Just look at this," she said.

Nancy's eyes widened when she read the t.i.tle: "Hot New Pet Craze-Whistling Mar- mots." The sheet had been photocopied from a magazine. In the article the words native to Yellowstone were highlighted in orange.

Nancy's heart began to race. "Where did you get this?"

"I was sitting in the lobby," Bess explained, "when a rich-looking couple came in and stopped near me. As they moved away, I noticed a piece of paper on the floor, so I picked it up."

"Hmm." Nancy scanned the page and read out loud. " 'Rock star Randy Dean's fondness for collecting marmots has made the creature a sought-after pet among the rich and famous.

According to one U.S. wildlife specialist, some people are willing to pay as much as five hundred dollars for one of these animals.'"

"Randy keeps a bunch of marmots on his California estate," Bess said. "According to the article, one of them escaped. A neighbor found it in her kitchen, munching its way through a box of cereal. The story made the newspapers, and ever since then people have wanted marmots."

"That's very interesting," Nancy said slow- ly. "I guess we should find out the couple's names and where they come from."

Bess grinned proudly. "They're Gerald and Edith Turkower, and they're from-just guess -Bel Air, California."

Nancy stared. "How do you know?"

"Simple," Bess said smugly. "While they were registering, I checked their luggage tags."

"Good work," Nancy told her friend. "Tell you what," she added, "as a reward, I'll treat you to a cup of tea and a snack. I'll also fill you in on what I've learned so far."

The dining room had log walls and wooden ceiling beams. As they sat down at a table near the windows, Bess leaned forward and whis- pered, "Two tables to your left-those are the Turkowers."

Nancy casually glanced in their direction as the waitress arrived to take her order.

Then, just as their pie and tea arrived, a bellhop walked through the dining room, say- ing, "Nancy Drew, telephone call for Nancy Drew."

Nancy waved to him and identified herself.

"It sounds like an emergency," he told her, pulling a cordless phone from a holster on his belt.

"h.e.l.lo? Yes?" Nancy said.

"Nancy, thank goodness I got you," a breathless voice said. "It's Alicia Nivel. You've got to come at once. Ned's been hurt!"

Chapter Four.

NANCY clutched the phone so tightly that her knuckles turned white. "What happened?"

"We don't know," Alicia replied. "We found him on the floor at the command post uncon- scious. He must have fallen and hit his head on something. When he came to, he asked us to call you right away, so I drove down to the general store at Madison Junction."

"I'll be there as soon as possible." Nancy switched off the phone and sprang up from her seat. "Ned's been hurt," she told Bess. "I have to go to him right away."

"I'll go, too." Bess waved for the waitress and paid the check while Nancy went on ahead to get the car.

The fifteen miles to the campsite seemed to take forever. When Nancy turned in to the parking area, she flung the door open in one movement, then dashed up to camp and straight to the tiny cabin. Bess followed. In- side, Nancy saw Jack, Jennifer, and Alicia cl.u.s.tered around Ned with an open first-aid kit on the floor nearby. Ned was sitting propped up against the wall, holding his head in his hands.

"Ned!" Nancy cried as she rushed in and knelt beside him. "Are you all right?"

"I feel a lot better now that you're here."

Jennifer reluctantly moved aside so Nancy could look at the back of Ned's head. There was a huge b.u.mp and dried blood on it. "What happened?" she asked.

Ned shifted, and as he did, Nancy noticed something gleaming on the floor behind him.

She picked it up and tucked it into her pocket.

"Let me think. I was on my way over to the command post. The door was ajar, and it's supposed to be kept shut because there's a lot of valuable hardware in here. So I decided to make sure everything was okay. I got inside, and the next thing I knew, I was lying here with this lump on my head and the mother of all headaches. Somebody must have hit me."

Just then Bess arrived. "Ned," she gasped, "are you okay?"

"Hi, Bess," he answered, trying his best to sound normal. "Guys, this is Bess Marvin."