CHESTER is bored at his sister CHARLENE's wedding reception but is stopped from causing a scene by the late arrival of her twin CHARLOTTE (Lotty). He has no use for Charlene's new husband, VINCE, and even less for any of Vince's friends, including the best man, ROGER, who is sitting next to him. He takes Lotty outside to find out that she overslept after partying the previous night, and when they return Roger begins making advances toward Lotty, ignoring his own date in the process.
Chester finds her attractive and suggests to Lotty that she go along with Roger's advances and see if he is stupid enough to take the bait. He is, and Chester grabs NELVA on the rebound.
Nelva gets the bridal bouquet, Chester reluctantly gets the garter, and the two of them resist Vince's suggestion to throw bird seed instead of rice. As the newlyweds leave the reception, Chester nails the best man with a Jordan almond, just as he'd planned.
Chester wakes up alone, although Nelva had been with him earlier in the morning. He finds no sign of her in his apartment and no note from her, either. He goes to work and thinks about her off and on while doing his job of animal handler at a veterinarian office. Lotty comes over after work and they spend the evening reminiscing about growing up as triplets and talking a little about Nelva and usher boy.
Lotty drives home and the next morning arrives early at her work, a wrecking yard. She's a combination receptionist/dispatcher and the yard is hoping to begin receiving police impounds. She's not crazy about that since it will mean more work but no more pay: her boss needs to recover the money he spent on new tow trucks and on building a security cage around her desk and the impound lot. She needs more money because her rent is being raised, and her friend Sheila lets her know about an opening at an Indian Casino as a ring girl.
That night, as she talks to Chester and learns about the Stonehenge Weekend party he has planned for Saturday, someone steals her underwear out of the laundry downstairs.
It's “Stonehenge Weekend” when the sun slips down the crack between the apartments across the street from Chester's home. He holds a party to celebrate without telling anyone the reason for it, only the name. It's a costume party (they are all supposed to dress like Druids) and a cook out by the pool.
Half of the party gets thrown or pulled into the pool, including Chester. His watch is ruined, which he discovers too late. By the time he assembles everyone in his apt to see the Stonehenge sunset, the sun has already set.
While Chester and Lotty dance at his party, she tells him that his apartment needs to be fixed up, to be decorated. He objects, is glad that Nelva didn't show up to see his failure to produce the Stonehenge sunset, and some of his friends play cards to determine who gets to dance next with Lotty.
Chester and Sheila retire to the balcony. He, and maybe she, play back and forth about starting a romance, but before anything can happen Lotty comes out and interrupts them. Sheila mentions the theft of Lotty's underwear, and Chester is disturbed that Lotty didn't tell him about it. They agree to meet the next night at Lotty's. Sheila will bring over some laundry, and they will use that to try and trap the thief.
Lotty prepares dinner while Sheila gets her laundry ready and Chester lounges around. After a quick pasta salad they decide Lotty should be the one to wash the clothes since the theft may have been a personal thing, focused on her. Chester hides out behind the laundry room while the girls sit upstairs and, while he sees a couple people going in and out, the bait isn't taken.
Lotty gets hired for a UFO convention. She'll be wearing a silver spandex dress and hoping to attract crowds to the Obfuscated Video booth. Her friend Sheila will try to work with her and comes over for dinner. Chester is invited and gets the hots for Sheila, who's trying on the dress. Charlene calls, having just returned from her honeymoon, and invites everyone over the next night.
Chester goes to Charlene's home for the dinner and Roger, the best man from their wedding, is there. Vince begins boring Chester with an account of the honeymoon, cut mercifully short by the arrival of Lotty and Sheila.
Everyone sits around, drinking and later having dinner. After an extended meal of no fewer than seven courses served with and on all the new wedding gifts, the party returns to the front room. Charlene suggests they can watch the wedding video, but Lotty has another idea and asks if anyone wants to see the UFO videos she and Sheila will be selling at the show.
The group watch the videos, and only Roger is already conversant with the contents. As they sit through explanations of Roswell, other sightings, and an alien autopsy, he is buying it all and attempts to convince the rest of the group. Chester isn't convinced, and he wonders if the rest of the group are. Lotty and Sheila tend to side with Chester, and Charlene is leaning toward the True Believers.
Lotty and Sheila are at work at the UFO show. IGGY, their boss and owner of Obfuscated Videos, is happy with the results and even happier that he was interviewed for a TV program. The women get hit on a lot, as expected, and meet some of the other vendors and people in the crowd. As they're leaving the show, Sheila asks Lotty what Chester's doing that evening, and Lotty calls him up and hands Sheila the phone. The two of them set up a date for later that evening at a local bar.
Lotty is pissed about the date. She doesn't want Chester starting anything with her best friend and is afraid that it will put her in the middle when they break up. This is going against the rules, she feels, and while getting ready to meet them at The Beanery she gets madder and madder. She scrapes her car getting out of the parking lot, which upsets her even more. When she feels betrayed by Chester and Sheila she leaves the bar, giving Chester a final reminder to mind himself around her friend.
Chester wakes up with Sheila next to him. He takes her back to her home and they part on good company. He's afraid to talk to Lotty about it and calls Charlene, instead. She threatens to help Lotty kill him if he hurts Sheila, and Chester still isn't sure how he feels about her or about having a relationship.
Lotty goes to work at UFOCon and is pissed about Chester's fling with Sheila. She talks about it with her, and Lotty is afraid their friendship may be ruined since Sheila is being reticent and cold. They work the show together awkwardly, but things are improving when Lotty spots Chester coming to visit them.
Chester goes to the convention and takes his time before visiting the Obfuscated Video booth where Sheila and Lotty work. He picks up something for them to drink and receives a distant reception when he gets to their booth. He lets the girls work and talks a bit with Iggy before Charlene and Vince arrive, accompanied by Roger and Nelva. They talk about Chester's party instead of the unmentionable subject of his romance with Sheila, and when Nelva leaves to get something to drink Chester pursues her through the crowd.
Nelva lets Chester know that their one-night stand was just her way of getting back at the guy who dumped her at the wedding, and Chester is frustrated that he can't pursue it further. When they return to the Obfuscated Video booth, Sheila is missing and Lotty tells Chester she's in the lady's room crying. Chester and Sheila have a fight about his running off after Nelva, but over pizza and coke they begin to settle things. As they return to the booth she takes him back fully.
As soon as they get back, Lotty grabs Chester and heads off to lunch. They have a long and boring conversation with everything repeated a few times, and eventually Lotty feels better about Chester being with her friend than she did earlier. Lotty also lets Chester know that she's got a date with TONINO, the guy who works at the pizza counter and whom Chester has run into with Nelva, Sheila, and his sister.
Lotty has been ignoring Chester and Sheila, spending her time with Tonino. He takes her out for a weekend stay at an Indian casino, a couple hours drive away. She hopes for a romantic vacation, but Tonino is more interested in gambling than he is in Lotty. She wanders away, leaving him at the card table, and is approached by some boxing promoters who hire her as a ring girl.
Sheila and Chester go out drinking after he learns that Lotty is away for the weekend. He invites Charlene and Vince to join them, and they show up at the Beanery with Roger. They talk and dance and make arrangements to have dinner at Charlene's house next weekend.
A few days later Sheila needs to talk with Chester, and at a Denny's she tells him their relationship isn't working and she's calling it quits. She refuses to say what the problem is, but Chester's convinced that Lotty is behind it. He hasn't been able to talk with her since the UFO convention, and he gets drunk and falls over, busting a front tooth. He calls the only person he can come up with, his mom, and tells her he won't be going to Charlene's for the dinner.
Charlene talks to Chester from their parent's house, and he goes over to visit Lotty, who's home for once. She denies having anything to do with the breakup, but nurses his swollen lip and busted tooth. When he keeps confronting her about Sheila she locks her self in her bathroom.
Lotty hides in her bathroom, afraid to come out until she's certain Chester has left. She fills her tub with water and calls Charlene, who comes over to soak her feet with her sister. Lotty breaks down, revealing she's afraid of Chester and of having screwed everything up.
Chester, back home, drinks heavily and calls Sheila.
Chester goes to the dentist and has his tooth extracted, leaving him with an embarrassing, ugly gap in his smile. He takes a lot of painkillers and is afraid of going out and being seen. No one he wants to talk to wants to talk with him, and he spends the night drinking alone and moping, wondering what he's done wrong, and trying to come to terms with being exiled from Lotty.
Lotty and Sheila go back to the casino so Lotty can have her wardrobe checked for her ring girl job. Lotty can tell that something's bothering Sheila, is wrong with her, and is impatient when she only talks a little, and then,only about Chester. Lotty, evidently, has made Sheila choose between her and Chester. Lotty shows the promoters her clothes, and the two of them return to LA. Sheila is not acting like the friend Lotty expects her to be, and is annoyed by Sheila's behavior.
Chester decides to go to dinner at Charlene's once he learns Lotty isn't showing up. He worries about teased about his missing tooth, but hides it from everyone there. His parents and Roger are the only guests until Chester answers the door and Lotty and Sheila show up.
During dinner, Roger keeps coming up with conspiracy theories, which he believes. He makes an error when discussing Pearl Harbor, the day when the dinner is taking place. The triplet's mother's parents were killed during the attack, which Roger claims was permitted by the US government. They forgive him and after dinner he changes the subject to eating raw food. Everyone agrees to try the diet except Chester, whose refusal cements his isolation from everyone else, but earns him a little footsy-playing from Sheila.
After watching a movie Roger probes Chester. Since he doesn't believe Roger's theories, Roger thinks he must have some of his own. Chester goes through his personal boycotts, ending up with his refusal to buy diamonds. When Chester decides to call it a night and leave, Sheila asks for a ride.
Chester and Sheila have been together since the dinner, some three days earlier, and haven't talked to anyone. She and he visit the zoo and then, as a surprise, he asks if she wants to go the casino and support Lotty in her new job. They go there and get a seat directly behind where the ring girls sit during the fights. Lotty doesn't welcome them, but Chester's convinced it's just an act and that she's inwardly happy they're there. While she's parading around the ring and subject to leers and catcalls, Chester returns to supporting and defending her by acknowledging she's his triplet.