Not a happy ending

Carrie takes over the planning, while you just numbly agree. She'll pick her up near the airport with some bullshit excuse (Cassidy will be flying out on a two-week vacation soon), **** her, and bring her to an abandoned shack in the woods where you will fuck her and... kill her.

"This is wrong..." you tell her, near constantly, but your erection during the plotting says otherwise.

"No, this is great!" she replies, exuberantly, often while riding your dick. "This is your fantasy!"

You felt that this might be more of her fantasy than yours, but you don't press the issue. Carrie's quick turn towards homicidal wishes was very unsettling. Maybe you two weren't meant to be...

"**** me again!" she says, as she places your hands around her neck during the latest fuck session. Good practice.

A couple of weeks go by until Cassidy's vacation. Carrie shows you the secluded shack (apparently she used to fuck guys and girls here during high school), and helps make it livable. Or at least, fuckable. A route is made. A car is rented... or stolen. Carrie just shows up one day with a beat-up car with out-of-state license plates and says it will be useful.

You take the car to a rendezvous spot as Carrie goes to meet up with her sister outside of her airport hotel lobby. She apparently explained that their mother was sick and gave her a McCafe with a strong dose of sedative. And a stronger sedative via a needle in the car. As she pulls up in your car (why'd you let her borrow your car for this?) you see Carrie get out in her dark sunglasses and headscarf, smiling from ear-to-ear. Cassidy, Carrie's little sister and formerly her favorite person in the world, is slumped down in the passenger seat, pushed out of sight of traffic.

"I had to hide her from curious onlookers!" she says, exuberantly, as you help her pull her limp sister out of the car, looking for any onlookers yourself on this abandoned dirt road. You accidentally squeezed one of Cassidy's tits, and Carrie chides you, "Settle down there, Romeo. Save it for the shack!" She gives you a quick peck on the cheek as you unceremoniously drop the sleeping girl into the backseat.

"Although, if you want, strip her down and check for GPS devices. I'm going to hide her phone and change the plates." She skips away in her weak disguise as she leaves you with her sibling.

You shake a little as you take her clothes off. This is wrong. But your tent is bursting your pants button at the seams. Her shirt is empty, nothing in her bra. She stupidly had a fitness tracker on, which you remove to chide Carrie over. Nothing in her pockets, but some loose cash. Presumably her wallet was in her purse. You slip her bra off, and stare at her tits. Slightly bigger than Carrie's, but she still had a striking resemblance. At 21, Cassidy was smoking, and apparently a woman-about-town (not nearly as much as her sister, though). You peeled off her matching panties and looked at her full form in the sweltering heat.

"I'll take that!" said Carrie, yanking the panties out of your hand as you sniffed them. She tossed them into a pile as you exited the car. "Got to get rid of evidence," she said, burning her sister's clothes and belongings. You watched as her driver's license turned to ash, her picture burning away much like she would, soon enough. Carrie was hugging your side as you looked at the flame. She was so happy.

"I see Mr. Seven-Inch wants to come out and play." She looked back at the car worriedly. "If you want to fuck her, that's fine, but we should probably wait until she's awake and in the cabin. "Fuck me, instead!" she peeled off her own pants and sat on the hood of your car, opposite of the fire and the old car on this dirt road in the middle of dusk.

It wasn't the first time you fucked your Carrie on the hood of your car, but it was the best time you fucked your Carrie on the hood of your car. The adrenaline, the fear, the anxiety, all hyped up to the 11th degree, gave you an added boost to your lovemaking. No condoms, perhaps no birth control, you felt there were no consequences anymore to your actions. You were about to fuck... to **** Cassidy. And then snuff her. Kill her. You came as you choked Carrie (lightly) thinking about these future acts, filling your girlfriend's womb.

You helped put a throwaway dress onto Cassidy and rode in the backseat. It was dark now and Carrie tossed a bag toward you. "If she starts stirring, give her a shot of these," she said from the front seat, driving expertly with the lights off. You've never used a needle before, and a pit falls in your stomach as to how Carrie knows all this.

It was only an hour before you pulled up to the shack. It was several hundred feet off the dirt road, and you were surprised how well this car moved over the terrain. Carrie and you had made a path to the shack, but it was still a little craggy. You carried Cassidy by the head as Carrie grabbed her feet and brought her into the shack, and the barren Goodwill mattress you had prepared. You felt her stir a little, but didn't say anything.

"Well," said Carrie, gleefully, "do your thing!" She tossed you a pair of scissors from her prepared **** kit and began undressing. You cut away apart of the dress before accidentally poking into Cassidy, who just visibly stirs some more. "She's awake!" claps Carrie as she jumps a little. She gets back to removing her bra and panties as you cut off the last of Cassidy's one-piece dress.

The light in the cabin is provided by an old battery lamp as you stand over the girl and look down. You are in shadow, but she is in full view, as you peel off your shorts and your cock pops into the light. Her groggy eyes open a little, and then a lot, as she realizes the gravity of the situation. She's about to scream, but...

"Shhh..." says Carrie, pushing her own panties into Cassidy's mouth, before tying them around with a blanket. She has her arms tied before you even know it, as Cassidy begins kicking her legs. "Calm down, sis," she says, kissing her baby sister's forehead as she finishes double-knotting her arms over her head to an old drainage pipe. She straddles Cassidy's legs as you back further into the shadows, watching this all unfold from a distance.

Cassidy's legs are tied apart, as a look of betrayal, of pain, furrows her brow. You couldn't see Carrie's reaction, but you could hear it. "I'm sorry. I told him I'd help him do anything. And he wanted to snuff you." She shrugs as her sister thrashes.

Carrie stands up and comes next to you, giving you another peck on the cheek. "All ready for you, tiger!" she slaps your ass as you march forward, revealing yourself to Cassidy and prepare to fuck her.

And fuck her you did. You face little resistance, as her spread eagle form helps your cock slip into its sleeve. You grasp her breasts, her sides, her arms, and then her neck, as you pound into the poor girl who never did anyone wrong.

Carrie is rubbing your back as you **** and fuck this slut... but she's not a slut. This victim, who is facing the worst day of her short life. You want to cum right away, but Carrie is right. You've come all this way, you might as well go all the way.

Your hands tighten as her eyes bulge a little. You could hear her chokes through the gag, but it's not enough. Suddenly, hands cover yours, as Carrie has taken the opposite side of the fuck and kisses you, pushes your hands further down as you almost finish your fuck.