When Lavender was in fifth grade, her class had taken a trip to the Arizona Science Center, and during the educational program, one of the museum employees dipped a tennis ball in liquid nitrogen and then hit it with a hammer. The ball shattered into tiny frozen fragments.

As Lavender stared into her empty water bottle, she felt like someone had frozen her with liquid nitrogen and then smashed her with a hammer into tiny shards that could never be put back together again.

“Does anyone have any water left?’ she called in a hoarse voice to the others, who were sitting nearby.

Marisol and Rachelle shook their heads. John held up his water bottle and swished it around. “I’ve got enough for maybe one sip each.”

Lavender blinked. John’s bottle reflected in the sunlight and hurt her eyes.

“No, it’s your water,” Marisol told John. “You should drink it.”

But John shook his head. “It’s okay. I’ll share. Here, Lavender.”

Head pounding, Lavender forced herself to walk the few steps to John.

“We’re already dehydrated,” Rachelle was saying. “We definitely haven’t been drinking the amount that a person needs, especially when you’re doing as much physical activity as we are. At this point, a couple of drops aren’t going to make a difference.”

“Then I’ll drink your share,” Lavender said. She was so parched that every drop felt like it was the difference between life and death. But when she took John’s bottle, Lavender only let herself take one small sip. In silence, she passed it to Marisol, who took a sip, then to John, who took a sip before passing it to Rachelle.

In spite of her words, Rachelle pressed the bottle to her lips, but she did not finish the water like Lavender had expected. Rachelle left enough for John to drink the final drops. But he didn’t. In grim silence, John screwed the cap back on, and they stood and continued their climb.

Lavender felt a heavy weight descend over the group. Her confidence had completely dried up. They were in serious trouble. They were getting dangerously close to the twenty-four-hour mark that Marisol had told her about.

Only Rachelle was in denial. She chattered without pausing as they maneuvered between rocks and scrabbled uphill. Lavender grew almost dizzy listening to Rachelle bounce from one topic to the next. She blathered about her blisters, her soccer team, her favorite YouTube channel, her lost phone, which she thought had a warranty, and even the class’s missing telescope money. Rachelle tried to get everyone to say what they thought had happened to it, but Lavender didn’t make a guess. She was breathing too hard to bother with words.

Before long, Lavender stopped paying any attention. Rachelle’s one-sided conversation blurred into a haze of background noise, which lasted until Marisol’s voice broke through. She said exactly what Lavender had been thinking: “How do you even have enough energy to keep talking?”

The entire group came to a halt.

“I guess I’m in really good shape.”

“So’s John,” Lavender croaked, thinking of all the sports he played, “but he’s not talking a mile a minute.”

“My throat is too dry to talk,” John said.

In answer, Rachelle poked a lumpy yellowish-brown object out between her front teeth.

“What is that?” he asked.

“It’s a pebble.”

“But why is it in your mouth?” Marisol said slowly, as if she was talking to someone on the brink of a mental breakdown.

“Relax,” Rachelle said. “It’s just a trick my grandpa told me about. If you’re thirsty and there’s no water, you can suck on a rock.”

“Oh, I think I’ve heard of that before,” said John. “Isn’t it an old trick soldiers used?”

“Yeah, you get a lot more saliva in your mouth,” Rachelle said. “Then you don’t feel as thirsty.”

“That’s not going to stop us from being dehydrated,” said Lavender.

“No, it won’t,” Rachelle agreed. “But it’s better than nothing.”

“Heck, I’ll try anything,” said John.

He and Marisol both bent to find rocks. Lavender wasn’t so sure.

“Don’t you think it’s a bad idea?” she said. “What if you inhale it and choke?”

“I know the Heimlich maneuver,” Rachelle said.

“Or you bite down and crack a tooth?”

Rachelle shrugged. “I’m not saying it’s a good option. We ran out of those when the flood tried to wipe us all off the face of the Earth.”

Lavender’s head throbbed. Her face and neck hurt from yesterday’s sunburn. In fact, it was probably time to reapply her sunscreen, but her arms wouldn’t work. She couldn’t even search for a pebble like the others, because if she squatted down, she wasn’t sure if she would get up again. Resting her forehead against a nearby pine tree, she took deep, even breaths, trying to stave off the crushing fatigue and looming panic.

“Here.” Marisol stuck a pebble in her hand. “You should try it. It really is better than nothing.” Lavender tightened her fist around the rock.

“Let’s keep going,” John said. His voice was already less raspy than it had been only a few minutes before. “If we want to reach the top before night, we shouldn’t stop too long.”

As they began climbing, Lavender slipped the pebble between her dry lips. Moisture filled her mouth. It helped. Lavender tried to take even breaths without any sudden gasping or inhaling. She didn’t want to choke to death on a rock. She didn’t want to die, even though it was sinking in that she was closer to death than she’d ever been in her life.

With every grueling step, Lavender continued searching for a trail. She scoured the mountainside for any sign of human life: a trail, a tent, a bench—even litter would have been a welcome sight in that moment, some sort of tangible proof that they were not the only four humans left on the planet.

There was none.

No wrappers.

No plastic bottles.

No wadded-up papers.

Normally, Lavender would have loved to see such a beautiful, pristine landscape. It was a miracle to find a corner of Earth so untouched.

But the very remoteness of the area filled her with a nameless dread. If they didn’t reach the mountaintop and find a trail, or see a ranger station, or get a radio or cell signal, then all hope was lost.

She poked the rock around with her tongue. The pebble was a lumpy oval with some rough patches and some smooth. As much as she hated to give Rachelle credit for anything, it was helping.

But Lavender did not thank Rachelle. She didn’t say anything. As the afternoon wore on, even Rachelle gave up on speech. They were exhausted, weary, and scared.

Then there came a part of the hike so steep that Lavender wanted to cry. Here, a few of the angles had to be a for real ninety degrees, and they were no longer hiking but scaling rocks. Lavender’s hand—raw from the splinter—hurt with a sharp, stabbing pain that only increased when she had to pull and tug against boulders.

She was ready to quit, when John called out: “The peak! I can see it. We’re almost there.”

He was just a few feet ahead of her, standing on the edge of boulders so steep that it made her stomach drop.

“Be careful!” she called to him. “Don’t stand so close to the edge.”

“Come on,” he called down to her. “You’ve got this.”

But Lavender was utterly exhausted. With barely any food or water all day, she was nearly at the end of her stamina. Next to her, Marisol looked equally frail. Rachelle was just ahead of them, perched on a rock a few feet above their own. She twisted to look at them.

“You guys, he’s right. I see it. We’re so close to the peak.”

“Go on ahead without us,” said Marisol. She flopped her hand in an exhausted wave, shooing Rachelle away.

“No, not without you,” Rachelle said. “Leave no man behind.”

“What?” asked Lavender. She tried to clear her head with a little shake. It didn’t help; it only made the pounding worse.

“Something else my grandpa used to say. I think from when he was in the army.”

“Why are we talking about your grandpa?” Lavender asked.

“Because we’re not leaving you behind.”

“Why do you even care?”

“Because you look like you’re about to pass out,” Rachelle retorted. “I’m not leaving anyone when they look like that. So get your butts up here, both of you, or John and I will drag you the rest of the way up the mountain.” When neither Lavender nor Marisol moved, Rachelle turned around and called, “John! Come back.”

Rachelle gestured to him. He’d been leaning in the shade of a large boulder, waiting for them to catch up. Now he climbed back down. Lavender didn’t know how he did it. She couldn’t imagine making that climb once, never mind twice.

Lavender rolled the pebble around in her mouth, trying to moisten her throat. She was parched. Her mouth was a desert. The Sahara was a tropical paradise compared to her.

With a thud, John landed on the ground in front of her.

He reached in his backpack and grimly handed Lavender his water bottle. The last sip still swished around in it. She shook her head. She couldn’t drink the last of the water.

But he just held out his arm until she took it.

Spitting out the pebble, she unscrewed the cap and let the last bit of water drain into her mouth. It was the single most generous thing anyone had ever done for her, and it gave Lavender the strength to force herself to her feet even as Rachelle limped over to Marisol and heaved her up.

Once she started moving, a little of Lavender’s energy came back to her, and she found the strength to make it over the last few boulders. Maybe it was because Rachelle and John helped, calling encouragement and holding out a hand anytime a little extra effort was needed. They took a few rests, but Lavender did not make the mistake of sitting, leaning, or slumping over again. She knew they might really end up having to drag her if she did that.

At the last stop, when all four of them had a perfect view of the mountain peak, she turned to Rachelle and said, “Thanks for helping me. I know you don’t like me.”

“You don’t like me,” Rachelle said.

The first thought to pop into Lavender’s mind was I don’t.

They had never been friends. Rachelle had rubbed Lavender the wrong way since the first time she’d shown up at Wellson Elementary. When she’d introduced herself to the class on her first day as a new student, she’d stood in front of everyone and said, “My name is Rachelle Winchester, and my parents enrolled me at this school because they’re old friends with the principal.” She could be a smug little know-it-all.

Now Lavender found herself wondering whether Rachelle must have felt the same way about her. Before she could muster enough energy to ask, Rachelle answered the unspoken look stamped across Lavender’s face.

“You don’t have to like someone to do what’s right,” Rachelle said. “Doctors don’t have to like their patients. Teachers don’t have to like their students. Waiters don’t have to like their customers.”

“But it helps,” said Marisol, “when people like each other and are nice.”

“Yeah,” John agreed in a faraway voice, “it does.” And Lavender wondered if he was thinking about his parents.

Studying the three faces around her—streaked with dirt and scraped from running through the wilderness and chapped from the dry climate—Lavender felt a wave of affection for these three. Straightening her shoulders, she heard herself make a sudden vow: “Get me out of the wilderness alive, and I’ll never lie again and I’ll like all of you until the day I die. Seriously, you’ll be my best friends no matter what. I’ll have your backs for-ev-er.” She didn’t care if they believed her; in that moment, she knew she meant every syllable of it.

“Dramatic much?” Marisol asked with a weary smile, but Lavender heard a familiar teasing tone—the one Marisol used with her best friends. And Lavender found herself smiling, too. Marisol staggered a few steps forward. “Come on, we can see the peak. We’re almost there. I just know we’re going to see our campsite or find a trail or a backpacker or something. I can feel it.”

A light, bubbly feeling rose up in Lavender’s chest. It took her a few seconds to recognize the emotion. It was hope.