The ladies of “Real Housewives of Orange County” are notorious for causing trouble, but viewers have never seen anything like the feud that unfolded during Shannon Beador’s 70s bash. The veteran cast member arranged for the entire Season 11 cast and their husbands to gather for a groovy get together in the episode prior, but wasn’t prepared for the chaos that ensued in episode 5.

The episode opens with a preview of the brawl, which is far from the peace and love vibe of the decade, before catching up with Shannon and David Beador, who are putting together their looks for the event. The couple brings along their daughters, who bring their parents up to speed on some sex-ed related topics they’ve been learning about in school. David manages to — for the most part — dodge questions about his history of wet dreams, distracting his kids with the tacky costumes. He and Shannon find their outfits and hit the road.

The big night arrives and everyone who’s anyone in Orange County is there — even Vicki Gunvalson, who Shannon begrudgingly sent an invitation to via email in episode 4. She arrives at Shannon’s party with new gal pal Kelly Dodd after doing a few shots of tequila prior. Not long after walking into the venue, Kelly spots a familiar face. The acquaintance says hello and then reminds Kelly that when last they saw one another she was with another man. The “RHOC” rookie attempts to laugh off the awkward conversation starter while her husband, from whom she claims she was separated at the time, stands their uncomfortably making an “L” on his forehead. This should have been a clear sign to Kelly that she was in for a wild ride, but she, Vicki and her husband continue to whoop it up — oblivious to the drama that awaits.

Shannon and Kelly’s mutual friend retreats into the party and things seem to be going well for a while. At least, until she and another guest begin gossiping with Shannon about Kelly’s love life. It comes to light that Kelly, whom Shannon has already heard rumors about, was in a relationship while she and her husband were separated and was — according to Shannon’s source — left heartbroken when the relationship ended. It was then that she apparently returned to her husband.

The women decide to confront Kelly, who they think has heard the gossip while searching for Vicki’s purse. One of Shannon’s friends attempts to help, asking what the purse looks like, which makes Kelly irrationally angry. The pair begin hurling insults at one another and, of course, Shannon sides with her friend. She tells Kelly to hear her out, which only further aggravates her. Kelly launches an attack on Shannon, insulting her outfit — at least, I think calling her Mrs. Roper from “Three's Company” was intended to be an insult — and slamming her appearance.

Shannon quickly grows tired of Kelly’s tequila-fueled antics and throws her out after insinuating that she’s a drunk. Before Kelly and her husband can leave the party Shannon shares with her a story she heard alleging that Kelly had an affair with her neighbor. The pair somehow end up in a strange verbal argument shouting “who” and “you” back and forth at one another until Kelly stops to assure Shannon that she is too “ugly” for her to ever consider being friends with.

Meanwhile, Vicki is being attacked by Shannon’s husband, who can’t seem to let the Season 10 Brooks Ayers drama die. He calls Vicki a “scumbag,” a liar and “the lowest of the low.” She and David wind up nose-to-nose screaming at one another while the rest of the party looks on in horror. While exiting the party Kelly adds one final jab, telling David she is not at all surprised he cheated

Once inside their limo, Vicki places an angry phone call to Brooks — who does not answer. She decides to leave a voicemail, telling him that “it’s been nine months” since his cancer scandal and she’s still picking up the pieces. Vicki pleads with him to return her phone call and place one to David, clearing the air about her involvement in the fake cancer drama.

While it seems there is no hope for the relationship between Kelly and Shannon at the close of episode 5, previews for next Monday’s installment suggests that with clear heads both women may have a change of heart. The pair plan a sit down — but will it go better than the party? Tune in to Bravo on Monday at 9 p.m. EDT to find out.

Kelly Dodd, Vicki Gunvalson Kelly Dodd (left) and Vicki Gunvalson find themselves at the center of some ugly drama during Season 11, episode 5 of “Real Housewives of Orange County.” Photo: Getty Images