That's the question I've been asking myself ever since George, Bess, and I left on a bike tour around the beautiful Mystic Lake Park. What we thought would be a chance to take in some scenery and bond with nature has been nothing but disaster. Our tents were stolen, we were drenched in a nighttime downpour, and our food disappeared. And we've only been gone for twenty-four hours!

Now I'm starting to think that someone's out to sabotage the tour.

It couldn't be one of our fellow cyclists. Could it?

CHAPTER ONE

Just One Small Problem

“I CAN'T BELIEVE I'M DOING
this,” my friend Bess Marvin muttered, poking morosely at her eggs.

George Fayne, my other friend and Bess's cousin, elbowed her and grinned. “It's because you love me so much,” she said. “Just remember that.”

We were all eating breakfast at the quaint inn where our upcoming three-day bike tour around the scenic, sprawling Mystic Lake Park was about to start.
George's parents had bought the trip for all three of us as a birthday gift to George, and they'd come to drop us off so we wouldn't have to leave our cars. Bess wasn't exactly as thrilled about the trip as George and I were. In fact, she was distinctly unthrilled.

“It'll be good for you, Bess,” Mr. Fayne said. “Get out of town for a few days. Get back to nature. Get some exercise.Â .Â .Â .”

Bess sighed and looked balefully at her cousin. “Why can't you be really into outlet shopping?” she asked. “Why can't your most dearly held birthday wish be, like, sitting on a beach in Saint Thomas for three days?”

George shook her head. “Because I'm not you?” she retorted.
“Come on, Bess. This will be fun. I bet you'll end up loving it.” Though they were related, Bess and George couldn't be more different from each other. George was sharp, sensible, and outdoorsy; Bess was cheerful, fashionable, and decidedly not outdoorsy.

“Like I've been loving all our practice rides?” Bess asked snarkily, then couldn't help breaking into a smile. George and I both started laughing.

“Come on, Bess,” I said, gently nudging her. “You only cried for the first hour last time!”

The truth was that Bess had been a pretty good sport on the practice rides the three of us had taken around our hometown of River Heights. We'd started at ten miles and worked our way up to thirty-five, which was the length of the rides we'd be taking on the tour. I was no athlete, but I kind of liked the bike rides; it was exhilarating whooshing through the town, almost like you were flying. I'd been sore for days after the first couple of rides, but gradually I'd gotten stronger. After our last ride, I hadn't had to take even one aspirin.

“Ooh, look,” said George, pointing at a tall, honey-blond girl who'd just stepped into the dining room. She was wearing bike shorts and a slim tank top, and her hair was pulled back into a sleek low ponytail. Behind her came a boy about her age, also with honey-blond hair, but his was cut short and matched the stubble on his face and chin. He wore a pair of cargo shorts and a baggy T-shirt that read
A LEGEND IN MY OWN TIME
. “I think that's Caitlin and Henryâthey're twins, and
they're leading the tour.” Our tour was run by a business called Adventures & Company that George said ran lots of these types of trips, but Caitlin and Henry had been featured online as the coleaders of our particular trek.

Caitlin smiled and headed toward us, gesturing for Henry, who looked less enthusiastic, to follow. “Hi, I'm Caitlin Moorehead. Are you all here for the bike tour?”

“We are,” said Bess, standing and offering her hand. “I'm Bess Marvin, and this is my cousin George Fayne and my friend Nancy Drew.”

Caitlin and Henry shook each of our hands. “Welcome,” said Caitlin. “I think we're going to have a lot of fun.” She smiled, but I couldn't help noticing that there was something tense behind her smile.

Then again, maybe I was reading too much into it. I have a tendency to do that sometimes. See, my thing is solving mysteries. My friends love to tease me about it, but they're always happy to join me in cracking a case. Together we've snagged more than our fair share of crooks in River Heights.

If there was something odd in Caitlin's expression, Mr. Fayne didn't seem to notice. “I'm Russ Fayne, George's dad,” he said.

“Nice to meet you,” Caitlin said, shaking his hand. “It's beautiful up here, isn't it?”

Mr. Fayne smiled, but his expression quickly turned serious. “And what are the safety procedures on a trip like this?” he asked. “What if, for example, there were an emergency?”

Caitlin nodded, looking unruffled. “Well, I'll always have my satellite phone with me, so we can contact emergency services even when we can't get cell service,” she said. The website for the tour had made it very clear: There was little, if any, cell service in the Mystic Lake region. “But I've also taken several courses in first aid, including CPR and child CPR. And I carry a full first aid kit, of course.” She paused, then flashed that same tense smile. “I've been a cyclist on at least ten of these trips, though, sir, and nothing's ever gone wrong beyond some bumps and bruises. I wouldn't worry too much!”

Mr. Fayne didn't smile. “And what is your background?” he asked. “How does one become qualified to give a tour like this?”

Again, Caitlin didn't seem bothered in the least as she launched into a description of how she'd grown up doing long-distance biking trips with her parents, camped all over the country, was a varsity athlete in high school, and was planning to study environmental science at Yale in the fall.

“Yale?” George asked, her eyebrows raised. “Wow, that's impressive.”

Henry smirked. “My sis is too modest to tell you, but she's going on a full merit scholarship from Grayson Industries, a biotech firm in our town,” he put in. “She beat out loads of impressive candidates with her 4.5 GPA!”

Even Bess looked impressed by that. “How did you get higher than a 4.0?” she asked Caitlin. “Isn't that the best GPA you can get?”

Caitlin rolled her eyes, looking embarrassed. “It's the way our school counts advanced placement courses,”
she said. “You get some extra points. No big deal.”

But Bess still looked puzzled, as though she was trying to do the math in her head. “How many AP courses did you take?” she asked.

Caitlin was turning slightly pink. “Eight,” she replied quietly.

“Wow,” Bess said breathlessly, shaking her head. “Well, I guess I should feel confident putting my life in your hands!”

She turned to Henry. “What about you?” she asked. “You're coleading the ride, aren't you?”

Henry gave her an easy grin. “I am. But only because the tour company insists on having two people lead, if they're under twenty-one. And it makes my parents happy, honestly. Caitlin's done most of the planning. She's the overachiever in the family. For instance, while Cait's up pulling all-nighters next year, I'll be relaxing in the south of France!” He elbowed his sister. “I'm taking a year off to travel.”

Henry smiled as he said that, I noted, but Caitlin didn't. She turned back to us, all business.

“Are there any other questions I can answer for you guys?”

As Mr. Fayne interrogated Caitlin and Henry some more, George reached over and touched my arm. “Let's make sure we have all our gear together,” she suggested.

“Sure,” I agreed, and got up from the table to follow her and Bess out to the foyer, where we'd placed our packs.

We each had a large backpack containing a few extra clothes, changes of underwear, toiletries, aspirinâthe bare essentials. Caitlin and Henry had provided a list of items we'd need for the trip, but they didn't include too much. “Probably so we don't get bogged down with stuff during the ride,” George had noted happily. We all also carried a big bottle of water, and George's parents had gotten us some protein bars, “just in case.” (Meals were included in the tour, but the Faynes didn't want us to get hungry.) The Faynes had also sprung for a super-fancy, superlight tent that the three of us would take turns carrying on the rides and share at night. It
was separate from the packs, and George suggested that we draw straws to figure out who would take it first. I “won,” so I would carry it on the first leg of our trip, until lunch today.

As George and I peeked outside, where our tour-issued bikes were waiting, Bess sauntered up to us, took one look at the packs, and shook her head. “I hope you know,” she said, “that this is by far the most outdoorsy thing I have ever done.”

“OMG, me too!” a female, slightly nasal voice piped up from the top of the stairs, and we looked up to see a curly-haired brunette with startling blue eyes walking down, carrying a huge backpack and tent. “Are you guys leaving on the tour?”

“We sure are,” George said, smiling. “We're really excited. I'm George, and this is Bess and Nancy. You areÂ .Â .Â .Â ?”

The girl smiled, revealing a slightly crooked bottom tooth. “I'm Zoe. Zoe Ferullo. Gosh, I'm so glad to meet you guys. I don't know anyone on this tourâI signed up to go with my friend Gemma, who is totally outdoorsy,
but then she backed out at the last minute. She got mono.” She paused, looked off to the side, and smiled wickedly. “I told her that would only make her as lazy as I am, but she wasn't buying it! Haw, haw, haw, haw.”

Zoe bent over laughing at her own joke, and Bess giggled too.

“Girls?”

We all looked up to see George's parents approaching the doorway from the breakfast room, already getting misty-eyed.

“It's about time to get going,” Mr. Fayne said, walking over to George and putting an arm around her shoulders.

I smiled at him. “Caitlin and Henry passed your interrogation?”

Mr. Fayne nodded and smiled. “Just be happy you have Georgia's mother and me looking out for you girls.”