Dean burst into the cabin with gusto, bringing a rush of cold outside air with him. He shut the door with his hip, balancing a stack of pizza boxes in his arms, and announced something that Mo couldn't hear through her headphones. Mo fumbled with her iPod, cutting off Jack White's thin voice and his ex-wife's steady drumbeat.

"What?" Mo said, blinking between Dean's determined stride and Sam's startled frown.

"Got a case," Dean repeated. He didn't look toward where she and Sam hunched over their new (cheap and barely functional) laptops, scouring the internet for potential lore resources that could contain information about Leviathans. Instead, he dropped the boxes on the counter and rummaged in the cabinets for plates.

"I thought we were focusing on stopping Dick," Sam said. "No more side quests until we handle the Leviathans? I think those were your exact words."

Dean sighed, turning to Sam with a plate laden with pepperoni pizza slices in hand. "Garth called. Something weird happening in Kansas. But since he's handling Mo's hotline, he can't swing it on his own. And we owe him for that demon in Delaware."

Sam cringed, as he did after any reference to his contrived marriage, and grunted his agreement. Mo didn't blame him. That story had been less fun and far creepier than she anticipated. Though with a demon deal involved, she should have known it would be a gruesome tale. And now Castiel's fate was left in the claws of one of those monsters…

Mo shook her head – as much as she lamented abandoning the angel to Meg, she needed to focus. She closed her laptop and made her way to the pizza. "We heading out tonight or in the morning?"

She loaded a few slices onto a plate and froze when she realized no one had answered her. She spun to face the Winchesters who were watching her cautiously.

"You can't be serious. You're leaving me out of this?"

Dean slid into a chair at the table. "Mo, it's not—"

"I'm at my peak physically now. I'm not gonna hold y'all back."

"That's not what I'm—"

"Garth's my friend. If he's tied up with hunter calls, that's my fault. I should help."

"That is not your—"

"And should we really be separating with shit as dire as it is? You said that—"

"Woman, would you let me explain?" Dean interjected.

Mo crossed her arms and leaned against the counter. "Do your worst."

Dean sighed. "We're all on the same page here that Garth is getting our help. Deserves our help. But I also agree that shit is dire. We can't afford to shelf this Leviathan hunt for any amount of time, even for one case. Someone's gotta be the A team and keep working on this while we sort things out with Garth. Mo Mooney – lore expert extraordinaire – that oughta be you. And you can do a hell of a lot more here than in the backseat of a Charger on the way to Junction City, I know that much."

Mo stared into Dean's steady green eyes for a long moment before letting the air out of her lungs with a huff. "Do you know how annoying you are when you make sense? Like, genuinely, I want to strangle you."

"Not really my thing, but, hell, I'll try anything once," Dean said with a wink and a sleazy smile.

Mo snorted, and Sam interrupted before she could retort. "Right, so Dean and I will leave for Kansas in the morning. It doesn't sound like Garth's case is urgent enough to warrant driving at all hours of the night."

Mo raised an eyebrow toward Sam. "So you are going with Dean then? Did I miss one of your eye-contact conversations that confirmed this?"

"Our what?" Dean said with a squint.

"You and Sam tend to just," Mo gestured vaguely between the brothers, "look at each other and have entire discussions and understandings in an instant. I mean, I'm a hunter – I pick up on non-verbal cues too, but this is transcending the need for speech altogether."

Dean rolled his eyes, and Sam gave Mo a soft smile before replying. "Guess that can happen when you've spent about three decades in each other's pockets."

Mo tilted her head to the side. "Huh. Dean did that with Castiel too. How long has he been around?"

Sam's eyes widened in warning, and Mo's heart sank. She had just resolved not to tease Dean about whatever he had going on with Castiel, and she put her combat boot-clad foot in it within two days. But Dean let out a short laugh. "Jealous, Mo?"

Mo grinned with relief. "Absolutely. But I'm quick. I'll get in on this secret language eventually."

"Nah, you like the sound of your own voice too much," Dean said.

Mo nodded gravely. "And you'd miss it if it was gone."

Sam and Dean insisted that Mo take the bedroom that evening so that they wouldn't disturb her when they left first thing in the morning. Dawn had hardly touched the sky when Mo emerged into the hub of the cabin, but the Winchesters were already gone.

It had been less than a week since she showed up on the porch of this cabin at Dean's call. This was the first time she'd been on her own since that day, and the solitude settled over her like a scratchy old shawl. Mo spent most of her life alone. Why had it taken only a few days of sharing space with the Winchesters to make their absence leave her feeling prickly? She had itched to put distance between herself and her own family since she was a kid. What was it about Sam and Dean that had Mo longing for their proximity?

She shook off her contemplative mood and turned on the coffeemaker. Despite being on her own in a cabin in the middle of nowhere, Mo wasn't alone. She and the Winchesters had several layers of backup plans in place in case Leviathans caught wind of them, they had to burn the cabin as a safehouse, or any number of catastrophic events occurred. And all paths led to them finding one another. Mo took far too much comfort in that knowledge than she'd like.

The Winchesters explained that Frank had located a lot where Dick Roman was constructing some kind of laboratory. While they were separated, they agreed it would be safer if Mo stuck to Leviathan lore research rather than any attempt of surveillance of this restricted building site.

On her second day at the cabin, she found herself beaming at her laptop screen. The University of Chicago library had a promising new rare book collection of Judeo-Christian history. The access waitlist for non-university applicants was several weeks, so Mo fashioned a student ID, texted Sam that she was following a lead, tossed her duffel bag into the gold Malibu she stole last week, and hit the road to the Windy City.

She booked a motel outside of the city beside a regional train station that led right to the university. On her third afternoon tucked into the library's silent, stuffy reading room, her hands sweating under the latex gloves she used to turn the ancient pages of yet another tome debating the ethics of the Old Testament, her phone rang.

Ignoring the glares of at least three librarians, Mo pulled her phone from the pocket of her jeans and answered with a whisper. "Yeah?"

"Get somewhere safe so we can talk. Something big's happening."

Mo's veins turned to ice at Dean's urgency. "Call you back in five."

She passed the priceless book to a librarian with a heap of apologies for her rudeness. Then she slipped into a single-user restroom and locked the door.

"You okay? You notice anything off?" Dean greeted her when Mo returned his call.

"No, just your typical afternoon, hiding in a library bathroom. Are you okay? What's going on?"

Dean sighed before diving into a hefty explanation. He received an email from Frank, auto-sent when someone attempted to access his hard drive. Since Frank was murdered by Leviathans, it was safe to assume they were the would-be hackers too. The drive contained intel about Sam and Dean – their current identities and credit cards, everything that kept them off the grid. If the Leviathans got to that data, the Winchesters were screwed. Sam got a GPS lock on the device, and they're preparing to steal the drive back as they spoke.

"Frank never knew your name. You wouldn't be in his files at all. You're safe from this mess and you should stay that way. Keep reading, okay? We'll call you when we've handled this."

"For fuck's sake, Dean," Mo growled. "You need all hands on deck for a heist of this magnitude. Don't be an idiot. Let me help."

"This ain't a hunt, Mo. We're not fucking around here," Dean said. "The hard drive is in the Roman Enterprises HQ, the center of this shit show. You think we're ready to charge in there with our guns blazing? We gotta play this smart."

Mo blinked. "The one in Chicago?"

"Yeah."

"Dean, I'm in Chicago right now."

Dean let out a string of curses, and Mo waited with her heart pounding in her throat. "Call you back in five minutes."

It was Mo's turn to swear as Dean hung up. She glared at her reflection in the bathroom mirror, flecked with water stains. She was sure Dean was conspiring with Sam behind her back about what to do with her. Where to command her. When had she become complacent enough to serve as the Winchesters' pawn?

But Dean was right – Mo should keep as far from the Leviathans as possible, and this mission would put her in their lair. They were nowhere near prepared to face the Leviathans head on. Then again, her anonymity could be their strength. If she was on the monsters' radar, she would rank low on their list of threats, unlike the Winchesters who shared the title of public enemy number one.

Her phone chimed, and Mo answered with a cranky "Yeah?"

"We're heading your way now and should be there tomorrow afternoon. Sam found the Roman Enterprises employee currently in possession of the drive. Charlotte Bradbury. Can you check out her place to see if you can find anything about what it might hold? I'll text you the address."

"It's after 5," Mo mused with a glance at her watch. "She'll be home from work. I'll pop over after rush hour tomorrow morning."

"Don't go anywhere near Roman Enterprises in the meantime, all right?" Dean growled instead of acknowledging Mo's amendment to his plan. "We gotta stay on the perimeter until we know what we're dealing with."

"Roger that," Mo said. And she meant it. She'd never tangled with Leviathans before. Based on what she heard from the Winchesters and Jody and… what they did to Bobby… Mo had hoped she would never encounter them at all. Now this battle seemed inevitable.

Mo slept fitfully but arrived at the building that Dean described in the middle of the morning. She slipped into the lobby without the staff blinking an eye and picked the lock to the apartment with ease. Stepping inside, Mo hummed in approval of the open floorplan. A wide couch was parked in front of a massive TV connected to several gaming systems. The tidy kitchen table was wiped clean, though every other surface in the place held a superhero figurine, fake sword, or fairy-like accessory.

Mo longed to study each item in detail, but she focused on finding anything that looked out of place, as if its occupant had experienced a midlife crisis, was being blackmailed, or had been murdered and replaced with a lethal shapeshifting monster. Though the bookshelves were packed with fantasy stories, they contained no supernatural lore, no hint that this Charlotte Bradbury knew the spooky creatures in her books actually existed.

She couldn't tell whether she was relieved or worried to end her search empty-handed. Were they dealing with an average, nerdy woman? Or were the Leviathans just that good at covering their tracks?

Mo didn't have time to ponder for long because a key rattled in the door and Mo's heart stopped. She spun frantically, her admiration of the open floorplan evaporating. The lock clicked, and Mo threw herself behind the couch.

The door banged open and slammed shut abruptly with the lock clanging back into place. Light steps pattered toward the kitchen accompanied by frantic, shallow breathing. Mo bit her lip – this wasn't a monster. This was a frightened human who just discovered that monsters were real.

Mo took a slow, even breath and let it out. Comforting civilians was not her strong suit. She usually let other hunters do the leg work of talking to witnesses on a case. Mo's people skills were… rusty. But she fought for some semblance of calm for the sake of the girl on the other side of the couch. That was the job.

"Hey, I'm in your apartment and I shouldn't be," Mo called.

The woman yelped, and something crashed and shattered on the tiled kitchen floor.

Mo waited through muffled swearing and shuffling until she got a response. "I'm armed. Just get the hell out, and I won't call the police."

"I actually wanna talk to you, Charlotte," Mo said, still crouched behind the couch. "I think you stumbled upon some scary shit and I'm here to help." She was met with silence, so Mo continued, operating on a great deal of assumptions. "You saw the files, right? You know borax hurts these things. I have some here. I'll prove I'm not one of them. I won't move, but you can come see for yourself."

For a beat, nothing happened. Then tentative steps approached, and a crown of bright red hair peered around the couch followed by wide green eyes. As their eyes locked, Charlotte Bradbury stiffened and moved fully in front of Mo. She brandished a kitchen knife in each hand. Mo held back a wince at the looseness in the woman's wrists. She would barely cut Mo's cotton shirt with a grip like that.

Mo settled into a comfortable seated position with both hands raised where Charlotte could see them. "Didn't know what was coming through that door when I heard the key, so I just dove."

Charlotte nodded as if Mo's explanation made perfect sense and jutted her chin forward defiantly. Then she slid a box of store-brand borax across the wood floor with her foot.

"Use mine," Charlotte said with a quiver in her voice. "Now, please."

Mo frowned at the powder and grabbed a handful, coating her palms in the white residue. She lifted her hands for Charlotte to observe, and the woman relaxed when Mo's face remained composed.

"It works better when you mix it with water," Mo advised. "Getting splashed in the face with this stuff tends to smart more than a dusting, you know?" She pulled her spray bottle of her homemade borax solution from her jacket pocket. "You next, if you don't mind?"

"Yeah, of course, totally," Charlotte chirped.

Mo slid the bottle in Charlotte's direction, and she put one of her knives aside to spritz the chemical onto her wrist. Nothing happened.

Charlotte let her eyes drift back to Mo. The warm green of them was framed by dark lashes and furrowed coppery brows. This girl was all vibrant colors, and each new shade of her was captivating. "We good?" Charlotte said, her voice tinged with curiosity now rather than fear.

Mo didn't have to fake the serene smile that overtook her lips. She nodded toward the knife still clutched in Charlotte's hand. "You tell me, Charlotte."

She wrinkled her nose and twisted her lips to the side, and Mo's chest swelled with fondness.

"How about you call me Charlie and tell me who the fuck you are?"