Our favorite girls are packing their bags for a trip Sin City! But it looks like they’ll be witnessing far more sin than the actual city of Las Vegas in the upcoming episode of ABC’s “Mistresses.”

In episode 6, titled “What Happens In Vegas,” Joss (Jes Macallan) and Harry (Brett Tucker) will get swept up in the magic of the Nevada-based city, prompting the two lovebirds to exchange their vows early.

“Let’s get married tonight!” Joss eagerly says to her fiancé in a promo video for the upcoming installment, only to have Harry agree with her ingenious plan. “I can’t believe how well things are going for us,” Harry speaks of the dynamic duo’s success after both their careers have taken off. But it looks like the handsome Aussie forgot to knock on wood because shortly after his statement, Joss finds herself in a heap of trouble.

While walking down the hallway of her glamorous Las Vegas hotel, Joss hears the alarming noise of a woman screaming. That’s when she spots her new business partner Reza (Micky Shiloah) acting aggressively toward a woman who was begging the nephew of the restaurant guru Jonathon (Navid Negahban) to leave her alone.

“Reza, let’s just calm down,” Joss says to the man who has been acting as her “very generous” host in Las Vegas.

Reza, however, has no plan to cool off. Instead, he gets even more charged up and tells Joss to “mind her own business” before what appears to be him laying his hands on her. But doesn’t Reza know that Joss has been practicing self-defense twice a day since she was beaten and tied up by Wilson (Jarod Joseph)? Looks like he’s about to find out just what happens when you make Joss Carver angry … and he definitely won’t like her when she’s angry.

Meanwhile, fans will learn who was knocking on Karen’s (Yunjin Kim) door in the final scene of episode 5 — and we have a feeling the mystery visitor will shake up Karen and her daughter’s life with his unexpected visit.

“Mistresses” Season 4 Spoilers Karen (Yunjin Kim) will get a surprise visit in Season 4, episode 6 of “Mistresses.” Photo: ABC

“Mistresses” airs Mondays at 10 p.m. EDT on ABC.