"Your deepest, darkest secret. 'Fess up."
A college sorority turned witches coven, and this is Dean's own fault. Took 'em for granted, put his hand up for the sorority gig while Sam looked into the school's new agers group. He's probably discussing crystals and moon phases and the divine feminine and loving it, while Dean's tied up in a basement and getting pawed by dangerous dabblers drunk on their own newfound power. "E—" he chokes, fighting to get the word out while some stupid truth spell compels him to spill his guts. "Evil bitch." He spits in her face, earns a slap as she gasps and jerks back.
She shrieks, and comes at him with black-lacquered claws out. She draws up at a titter from behind her. "What?" she directs at the circle of girls behind her. "Can you think of anything better?"
As one, they giggle and shake their heads. Ponytails swing and curls bob. "What is this?" one says. "Truth or dare? We know what he is, that he's gonna kill us if we let him go. You know what we have to do."
Black-fingernail's face blanches, already pale skin going white. "We can't kill people, okay? No killing. We agreed."
"We gotta do something," the other insists. "It's self-defense." She sighs. "One little spell, and he's gone. You won't even have to get your hands dirty."
Black-Fingernails shakes her head. "No." She turns back to Dean. "If we know his deepest darkest secret, he'll do anything to keep it hidden. We make him tell, then we turn him loose. If anything happens to us, it gets out, right? A hunter, I bet there's a lot he'd like to keep the police from finding out."
Dean laughs at that, because, seriously, fuck the police. What he's got buried is so much worse.
Black-Fingernails twists her hand in the air, opens her mouth to speak, and Dean can feel the spell tugging at him when there's a muffled banging from upstairs.
The basement door bursts open and Sam barrels down the stairs, looking for a target. He finds Black-Fingernails. "Untie my brother." He smirks, twitches the gun in his hands. "Witch-killing bullets," he says. "Set him loose."
He picked the wrong target. Two of the blondes throw themselves at the stairs, distracting Sam, and Black-Fingernails mutters something in Latin, completing the spell.
There's a struggle on the stairs. Sam's gun goes off, and one of the witches falls, tumbles backward, taking the other one with her. Sam steps over them, and the rest of the girls make a run for it, trampling their sister as they go.
As Sam trains his gun on Black-Fingernails, she starts to tug on the ropes holding Dean to the chair. "I was going to let him go," she says, her voice panicked and wavering. "It was the others. They wanted to kill him."
Sam glances at Dean for confirmation.
"It's true," Dean says. "And I can't lie right now so for the love of god, don't ask me anything." He pulls himself free as the ropes loosen, bends forward to untie his legs.
Sam twitches his gun again, and the witch backs up against the wall. "What did you do to him?"
"Truth spell," she says.
"What was the point of that?"
"Wanted something on me," Dean says, and he stands, ropes falling away. "Wanted security, guess she didn't think about the fact that if she knew my deepest, darkest secrets, then I'd really have to kill her."
Sam grins. "She wanted your deepest, darkest secret?"
"Shut up, Sam."
"How long does that spell last?"
"An hour or so," the witch says.
Sam reaches into his jacket, pulls out Dean's gun, passes it over. "Go," he says. "I'll be right out."
Half an hour later, they're back in the motel, packing their bags so they can get on the road. With several dead witches in a sorority house, they need to be gone.
"So," Sam says. "Did you tell her?"
Dean wants to mess with him, but the spell is still active, and he can't. "Nah. She got nothing."
"You didn't tell her about us?"
"You think the fact I'm screwing my brother is my deepest, darkest?" Dean says. "You've gotta be kidding."
Sam lifts an eyebrow. "So it's not?"
Dean realizes his mistake. "No. Sam, don't."
A smile spreads over Sam's face. "Then what is your deepest, darkest secret?"
"Shit," Dean says, before he starts to talk.