Andi Rose is getting friendly with the most popular girl in school, Madi Collins. She wants to have a Fourth of July get together, but her stepbrother, Zac Wild, has been left in charge while their parents are away. Zac initially says no, but when he sees who Madi is texting he changes his mind provided, of course, that Andi repay his kindness by fucking him. Andi agrees and Madi comes on over to help decorate. When Madi arrives, the girls start putting up patriotic décor and discussing how they'd serve military men. Zac tries to insert himself into the conversation, saying that he has been thinking of enrolling.
The girls taunt Zac about how he wouldn't make it in the military. Embarrassed, Zac starts heeling off his clothes to prove that he's a well-muscled specimen. The girls fight back by flashing their titties and peeling off the panties. Somehow in the scuffle, Zac winds up accidentally sinking his dick into Andi's pussy. Andi is surprised, but she does like the way Zac feels inside her. She encourages him to continue while Madi peels off her own clothes and masturbates at the sight of the stepsiblings fucking. That kicks off a full-blown threesome. The girls celebrate by getting on their bellies and working together to deliver a double blowjob to Zac's hardon.
Madi gets an opportunity to sample the goods when she climbs on top of Zac and impales herself for a reverse cowgirl stiffie ride as Andi does whatever she can to double down on her friend's pleasure. Then Andi gets on her knees to take Zac's dick in doggy while she muffles her own moans by eating Madi out. The girls switch spots, with Madi on her back so she can let Andi ride her mouth as Zac fucks her. When Zac sits down again, Andi climbs aboard to ride him. With Madi's fingers on Andi's clit, Andi is soon moaning and squirting her climax. After a second squirt, Andi moans in delight as Zac gives her a big creampie for Madi to lick clean.