Arielle focused on nothing but the road. She absentmindedly rubbed at her wrist, the weight of the handcuffs a phantom. She pushed away the images the police retrieved from the air vent. A pool of blood, skin, chips of bone. Her knuckles paled as her grip on the wheel tightened.

Turning sharply into the parking lot, she parked her car, her mother's last gift to her and jumped out, quickly taking the stairs two at a time. She pounded on the room's door, her heart thumping against her chest. Sam opened the door and Arielle walked in before he said a word. "What is it and how do we kill it?" she said as a greeting, her cold green eyes shifting between Dean and Sam.

"You're not getting involved," Dean said as he uncovered the shotgun and continued cleaning it out.

"Dean," Sam attempted.

"No. There's a reason why dad refused to take her on any more hunts," he said before his brother could continue.

Arielle walked straight up to him, her hands curled into fists. "I just got out of being interrogated. My house is a crime scene and I'm treated like a suspect, even though these people saw me grow up! For all I know, my mother is dead. And you two bail and expect me to wait patiently in the house that creature took my mother from? You either let me help or I'll do it on my own." Dean didn't look up once, but he set the shotgun aside, eyes focused on the bed. Her sharp eyes never left his form and she felt Sam shift behind her.

"We're not sure what took her or if she's even alive," the younger brother said quietly, placing a hand on her shoulder. "Dean, look, maybe- "

"Maybe what?" he said, looking up at his brother defiantly.

"She lost her mother," he said slowly but with emphasis. "Maybe we can understand what that feels like."

"Why do you think dad never told us about this kid, Sam?" he answered as he stood and grabbed the shotgun. "Why do you think he ripped out those pages?"

"Because- "

"Because he was protecting her!"

"Dad's dead, Dean," Sam retorted immediately.

"That doesn't matter! He didn't want Arielle to have our lives, okay? And we're gonna respect his wishes," he said with finality.

"I should have my own say in this," the blonde said, standing between the brothers.

"No," both Sam and Dean chorused. Before Arielle could respond, Dean scooped up his jacket and headed for the door. "Babysit the kid," he growled.

"Where are you going?" Sam asked.

"I'm going out!" He slammed the door as he exited and it elicited a sigh from Sam. Arielle sat numbly on the bed, gingerly rubbing at her temples as her hair cascaded down to hide her face.

"Is he always like that?" she asked tensely.

The sound of Sam laughing caused her to raise her eyes to him in surprise. "Welcome to the family," he said and she gave him a small smile. "Here," he said suddenly, pulling out his gun and ejecting the clip. "I'm gonna teach you a few things."

Arielle took the gun, examining it and then turning her gaze back to Sam. "Dean said- "

"I know what Dean said," he cut off, his voice calm and a bitter smile on his face." And I know what it's like to want revenge."

Night crawled up on them as they sat in silence. Arielle practiced disassembling and reassembling the gun as Sam cleaned a shotgun. "Sammy, what killed dad?"

The nickname caught him off guard, but he ignored it. "Demon." She nodded in understanding.

"You killed it?"

"Dean killed it."

"So it's over for you," she said, placing the loaded clip of the gun back in place, satisfied with the secure click. She looked up to find Sam's eyes on her.

"It's never over," he said quietly. Before Arielle could keep questioning him, the lights started crackling. Arielle tensed and stood the moment Sam did. He crossed his lips with a finger and she gave a slight nod. His lips barely moved. "Stay here," he said under his breath as he stepped to the door and opened it, checking the surroundings.

Another noise came from Arielle's right and the siblings turned to it, weapon's raised. The noise came again and Sam stepped in front of Arielle. "It's in the vents," she whispered as she pointed towards the ceiling.

He aimed the shotgun and fired. "Go!" he commanded and they rushed out the door. Arielle felt Sam right before, bounding down the stairs as well until they got to the parking lot. "Where's your car?" Arielle pointed out her cherry '67 Firebird. Sam's raised eyebrow caught her eye and she cleared her throat.

"Graduation present. Mom let me pick it out," she said in a strained voice. He gave her a sympathetic look and raised a hand. She clutched at her keys momentarily before tossing them to her brother. She rounded the car to the passenger's side and waited as Sam fumbled with the keys. Just as he caught the right key and gave her a grin, Arielle watched him fall back suddenly.

"Sammy!" she yelled, jumping over the hood to find Sam gripping onto the door handle. The sound of a familiar engine reached her and headlights illuminated the pair as she grabbed Sam's arm and yanked. "Dean, help!" The eldest sibling came into view and got a hold of Sam's other arm, pulling him free.

Reaching for the gun she had tucked into the small of her back, Arielle dropped to know knee and squeezed off two rounds. She could've sworn she heard something, but nothing could be heard except the purr of the Impala. Dean picked up the keys and Sam's dropped shotgun, tapping her on the shoulder to get her to stand. He gave a low whistle as he took on the girl's ride. He ran his fingers over the roof and gave it a pat before getting into it and turning it on. The engine came to life and Arielle watched him back the car up.

The combined headlights of the Firebird and the Impala revealed a sewer gate, still half open. Arielle pointed the gun into the gaping hole, noticing blood around the edge. "You winged it," Dean said, an impressive undertone in his voice. "Did you get a look at it, Sam?" When Sam shook his head, Dean frowned, rubbing at his jaw. "What the hell is this thing?"

"Should we go after it?" Arielle asked, still aiming her gun at the sewer gate.

"No, no. In that maze? That thing's long gone," he said. Sam leaned against the hood of the Impala, taking a deep breath.

"All right, so, we don't know what it is, but we do know who it's going after," he started, pushing off the hood and joining his siblings around the sewer gate. "Joe Barton, Arielle's mom- "

"And now Arielle. It was under her car, just waiting for her," Dean said.

Sam gave off a frustrated sigh. "It set a trap, and I walked us right into it," he said, giving Arielle an apologetic look.

"It wasn't your fault, Sammy," Arielle assured him. She earned a strange glance from Dean before he cleared his throat.

"Doesn't matter," Dean said, getting Sam out of his own thoughts. "You're right – there's a pattern. Joe Barton was a cop. I'm pretty sure he helped Dad. So we've got him, Dad's girl, and his daughter."

"All the people dad knew in town," Sam noted, his eyes going back to Arielle. "At least now we know why it's back."

Arielle met his eyes. "It wants revenge."