Dipper ran down the stairs, watching his feet so he wouldn't trip over his untied shoelaces. He was wearing his hiking shoes: dark red sturdy tennis shoes with thick laces. They didn't glow when he shone his new black light on them, but they made him feel like an adventurer.

At the base of the stairs, Mabel was struggling with her pack. "Grunkle Ford, this is really heavy," she said as she tried to heft it onto her shoulders. Then she wobbled and grabbed onto the banister for support.

Dipper hurried over to help his sister. "What's in there?" he asked. "We're not taking the whole Museum with us, are we?"

"Just some equipment," Ford said.

"I know it's a shock," Mabel said, setting the pack down with a thump, "but I'm a weakling."

"You're not a weakling."

"Grunkle Ford, I have noodle arms." She held out her skinny little arms for him to see.

Dipper went past them into the kitchen, where Melody hummed to herself as she made them sandwiches.

"Ooh," he said, hopping up on a stool, "you're cutting them into triangles! I love sandwich triangles."

"Me too," Melody said. "Do you like honey or jam with your peanut butter?"

"Both!" He grinned at her. "Hey, Melody, do you know how to make invisible ink?"

Melody frowned in thought. "I think I might have a recipe somewhere. You wanna try out that black light you found?"

"Yep!" He pulled it out of his pocket. "I'm gonna bring it along, just in case there's an invisible message somewhere in the bunker. There are all sorts of cool things in this house. You should've seen the back of Ford's lab."

"Oh, I've seen the lab. Your uncle nearly had to tie me to a chair to keep me from cleaning it."

"I think it's cooler when it's all dusty like that."

Ten minutes later, the Pines were all ready to go. Mabel and Ford had renegotiated the backpack sizes so that Mabel wouldn't fall over, the cute triangle sandwiches were all packed along with plenty of water bottles, the Journal was secure in Ford's pack, and the black light was secure in Dipper's. He didn't think he'd actually need it, but you never know. Gotta be prepared on an adventure.

"Be safe," Melody said. "Don't let any of those gizmos go off in your pack. Don't get split up. And for heaven's sake, don't come back dead." She hugged the twins and and adjusted Ford's turtleneck before stepping back to look over them. "Okay. You can go now."

"Bye, Melody," Dipper said. "Don't go crazy worrying about us!" He stepped up to the door and pulled it open.

And found himself staring into the wide eyes of Candy Chiu.

Her mouth was open, and her fist was up like she was about to knock on the door. She blinked as she stared back at Dipper.

"Oh, hi, Candy!" he said.

"Hi." She slowly lowered her fist.

"What's up?" he asked. "Come on in."

Mabel, who'd been impatient to leave all morning, threw her hands up in exasperation. Dipper ignored her.

Once Candy was in the house, and Mabel, Ford, and Melody had moved back so they weren't all squished, Candy coughed. "It looks like you're about to leave, but, uh, I just wanted to hang out."

"We are about to leave," Mabel said.

"Greyson's with his family today," Candy continued, "so I thought I'd come over here. But it looks like you're having a family day too."

"Yes," said Ford.

"Why don't you come along?" asked Dipper.

"No," said Ford.

"Where are you going?"

Ford started, "That's class—"

"On an adventure!"

"—ified."

"C'mon, Grunkle Ford, we should let her come!" Dipper turned to his great uncle. "We don't know what's down there, right? We might have to fight monsters and all that."

"Well, yes. Exactly."

"Candy can help! I've seen her take down bullies twice her size. And she's even helped take down magical clones before, right, Candy?"

"She did," Mabel said.

"I did?" Candy said.

"She's a lot stronger than she looks."

"Hey!" Candy protested. She punched Dipper in the arm. "I look strong!"

"Ow!" Dipper rubbed his arm. "Yep, yep, you do." He had almost said "cooler than she looks," so at least he went with the better of the two options. He still got punched.

"There won't be any need for fighting," Ford told Dipper.

"Wow, Mr. Pines," Candy said. "You're a worse liar than Greyson."

Ford glared at her. "Melody," he said, "is it wrong to punch a child?"

Melody patted his arm. "Yes, dear."

"Ha, bring it on," Candy said smugly. "I bet I could take you."

"Um, Candy?" Dipper said nervously. "Grunkle Ford is pretty fit for an old dude."

"She can come along if that means we can go," Mabel cut in. "Come on, we were so close."

There was silence for a moment as Ford and Candy stared at each other, neither daring to break the other's gaze. Dipper was seriously impressed — he hadn't ever seen someone hold Ford's death stare for so long.

"Fine," Ford said, still looking into Candy's eyes. "You may come, but only if you do everything I say, and don't take any unnecessary risks. That's the promise the twins are under as well."

"Fine," Candy replied.

Then, somehow, they broke each other's gaze at the exact same time.

Dipper decided it was a good idea to bring Candy along.

"Great!" Mabel said. "Can we go now?" She reached past Dipper to open the door.

"Wait," Ford said. "If Candy is coming, then we can give her a pack with some extra—"

"Grunkle Ford, come onnnnnn," Mabel interrupted. "We don't need all that stuff."

"We might."

"So where are we going?" Candy asked Dipper.

He lowered his tone to his Mystery Narrator Voice. "To the center of the forest, where few dare to go. There lurks a great treasure surrounded by an unknown danger that may kill us all."

Candy stared at him for a moment. He thought he saw her face get a little red, but it passed, and she assumed a nonchalant expression.

"Cool."

But Dipper knew he had impressed her. He had a really cool Mystery Narrator Voice.

The Pines (plus Candy) finally left the Museum, heading out for the forest. The morning sun shone brightly down on them. Dipper appreciated the sunlight warming his back. After all, there wouldn't be any sun where they were going.

~~~~~

Mabel shrugged her pack up higher on her shoulders and smiled up at the sun, wrinkling her nose and squinting at its brightness. It sparkled on the snow that blanketed the forest and made the trees look like crystal chandeliers.

Beside her, Ford kept a brisk pace through the forest. His footsteps squeaked in the soft snow, and the gun on his hip thunked against his leg. It was a just a stun gun, he'd assured Mabel, but she still decided to walk on the other side of him.

Before long, they reached the small clearing above the bunker. The tall tree at the edge of the clearing reached up through the snow. A small branch about ten feet off the ground had dustings of grey at its base, the only indication that it was metal masquerading as wood.

Mabel suddenly felt a strange sense of déjà vu.

She stared up at the tree. She'd seen it before. Well, of course she'd seen it before, she'd lived here for a weekend. But she'd seen it. . . before that.

"Mabes? You okay?" Dipper came up beside her.

"This tree. . ."

"It's the entrance to the bunker," Ford said.

"I-I know, but. . ." She circled slowly around the side of the tree. Then she gasped.

"What?" Dipper asked. Then he recognized it. "Oh!"

"Grunkle Ford," Mabel said, "this is where we found the third Journal!"

Ford's eyes widened. "It is?"

"Yeah!" She stepped up to the tree and felt around its trunk until her fingers found a ridge in the metal. She pulled the compartment open, revealing the small box inside. "I didn't notice the last time we were here, probably just because we were so preoccupied with. . . everything. But this is it. Step back, Dip, you're standing on it."

Dipper backed away.

Mabel pulled a small lever on the box, and another compartment in the ground slid open. "It was in here," she told Ford.

Ford knelt in the snow and peered into the compartment. After a long silence, he stood up again, brushing the snow off his knees.

"My assistant F built the bunker," he said quietly, "but he never told me about this."

"Does that mean he stole the Journals?" Mabel asked.

"I don't know," Ford replied. "That seems to be the most plausible explanation."

"But he built a secret compartment and hid one of them in it! Obviously that means he stole them, right? Unless he hid them to keep them safe, I guess, but safe from what?"

Ford held up a hand to stop Dipper's flow of words. "I don't want to make any assumptions," he said. He continued staring down into the compartment beneath the forest floor.

"Grunkle Ford?" Mabel asked softly. "What is it?"

"If F did steal the Journals. . . wouldn't he have hidden the other ones somewhere else? Somewhere far from here?"

Silence permeated the clearing.

After a long, sullen moment, Dipper took a single step forward, his light footstep deafening in the silent, frosty air. He put a hand on Ford's arm. "We gotta look anyway," he said. "Just in case."

Ford seemed to come out of his stupor. "Of course," he said. He took a deep breath. "Alright. Mabel, would you open the door?"

"M-me?" Mabel asked. She looked up at the branch towering above her head. The tree trunk between her and the lever had to be at least twice her height. "But you and Dipper would always open it, with a rock, or something."

"This is why I insisted you keep the grappling hook in your pack. You'll find it's far more accurate."

Not when I'm using it, Mabel thought. She didn't have a good aim. Or any type of hand-eye coordination. But she followed Ford's instructions nonetheless, shrugging her pack off her shoulder into the snow and rummaging through until she found it.

The grappling hook was heavy in her hands. She wrapped her fingers around the handle, cautiously sliding one finger to rest on top of the trigger. "Grunkle Ford, I don't think you want me shooting this thing."

"Nonsense, you'll be fine. Come over here by Candy and point it at the branch, there you go."

Mabel did what he said, and she appreciated that he wanted her to do it, but. . . didn't he get that she couldn't do this type of thing? The only times she'd done anything "strong" were when she was running on adrenaline.

Still, she stepped back so she could clearly see the branch and pointed the grappling hook, holding it tightly with both hands.

Grunkle Ford came to her side, crouching down to get to her eye level. "Good. . . a little to the left."

She adjusted her aim and swallowed.

"Okay, go for it."

Mabel pulled the trigger with her eyes squeezed shut.

The hook exploded from the chamber, and Mabel stumbled back at the kick from the gun. Ford caught her before she fell over. She opened her eyes in time to see the hook hit the tree far below the branch and fall back to the ground.

"Aw, come on, it's only a couple feet up," Candy said from beside her.

Mabel flushed.

"Candy!" Dipper exclaimed. Mabel glanced at his face; it was open and wide in shocked anger.

Mabel pressed the button to bring the hook back to the gun. The string whined as it sailed through the air.

"Mabes—" Dipper began.

"I got this," she said, standing up straight and clutching the grappling hook in her hands. She shot a little glare at Candy, who raised her hands and stepped back. The look on her face said she didn't think Mabel could do it.

A flare of determination ran through Mabel's spine. She wanted to prove she could do it. Anybody else would be able to hit the dumb branch with the grappling hook. She would too.

She adjusted the grappling hook in her hands, brought it up, took a breath, and fired.

This time, she managed to keep her footing. The grappling hook stayed on its course and hit the branch from underneath with a clank.

The branch moved up, and the tree started to shake.

"Go Mabel!" Dipper cheered. She grinned at him in a thrill of triumph.

"What is up with this tree?" Candy demanded as it started descending into the ground. Nobody answered her.

They all watched as the tree and the ground around it continued sinking down. Once it was far enough, it stopped with a grumble of machinery. Wooden stairs slid out to form stairs. A door at the base of the sunken tree opened.

"Okay," Candy said. "Definitely not a normal tree, then."

Dipper grinned at her, seeming to have forgiven her for being rude to Mabel. Lucky him. Mabel was still mad.

"Welcome," he said in his Mystery Narrator Voice, the one he sometimes practiced when he thought Mabel was asleep, "to the bunker."