The episode opens up with Brody and Kristin walking along the beach -- and discussing Heidi and Spencer's plans to throw their (6-year-old) neighbor a birthday party. Kristin admits she's weirded out by the whole concept, and reminds Brody of Spencer's erratic behavior at the barbecue. ("He was a little worked up" over Stephanie, Brody admits.) Talk turns to Audrina and Ryan, and Kristin tells Brody she thinks they're more serious than they're letting on. Brody feigns indifference, telling her he's only interested in Audrina as a potential hookup, anyway. Riiiight ...Meanwhile, Heidi's consulting with Lisa the party planner to make sure Enzo's seventh birthday is his best yet. Spencer arrives just as Heidi finishes telling Lisa to pull out all the stops. When he realizes that Enzo's small little shindig is already turning into a rager, he yells at Heidi for getting carried away and stalks off while Heidi assures Lisa that Spencer will, eventually, come around.Across town at 110 Speed Shop, Brody's showing Frankie and Taylor his new car -- and fielding questions about which girl he wants riding in the passenger seat. Under the boys' interrogation, Brody insists Kristin's just a good friend but says he and Audrina definitely have some chemistry. Right now, though, the only female he's willing to commit to is his car, Betty!Bowling time! Brody and Kristin are looking a little touchy-feely at Lucky Strike, but the moment's interrupted when Audrina and her boyfriend Ryan arrive. Brody runs over to hug Audrina hello, and can't resist making a little dig about Ryan's shoes. When Frankie complains about all the "couples bowling," Brody reminds him that he and Kristin are just friends who, occasionally, like to flirt. Seeing Brody and Kristin together, Ryan asks Audrina whether they're dating and she tells him they haven't been "boyfriend girlfriend" in years. Ryan then asks Audrina about her relationship with Brody, and she assures him there's nothing there (though admits Brody may still be interested). "He has a crush on me, he wants what he can't have," she explains.So what else is Brody doing besides crushing on Audrina? Shaking his head at the zoo animals, bouncy castle and giant elephant Heidi's rounded up in honor of Enzo's birthday. Together, Brody, Charlie and Taylor shake their heads at the kid-filled fiesta -- and reflect on how much Spencer's changed over the years. Soon after, Brody admits he's disappointed by the lack of hot moms in attendance, and when Frankie and Taylor ask him about Audrina, he reminds them there's plenty of fish in the sea. In other words? "I don't need to dip into [Ryan's] seconds."Meanwhile, Kristin and Audrina are having some girl talk while shoe-shopping at Madison (in Beverly Hills). Kristin asks Audrina for a relationship update and finds out that Audrina and Ryan are doing so well they're "ready for the talk." Kristin encourages Audrina to get everything out in the open, even though Audrina worries that Ryan won't be ready to commit. Talk turns to Enzo's birthday party (neither girl's going) and then to Spencer and Heidi. Kristin and Audrina agree that Spencer's been acting crazier (and more controlling) lately, but decide reaching out to Heidi would be pointless -- after all, when is she ever NOT with Spencer!?Back at Enzo's birthday, Spencer is telling Brody about Heidi's recent trip to Colorado. After deflecting the conversation away from Stephanie (Spencer claims he has no sister), Spencer goes off on a violent tangent about Darlene, saying she tried to "emotionally rape" his wife. When Holly objects on her mom's behalf, Spencer erupts, threatening to throw her off his property while Brody looks on, amused.Over at La Vida, Audrina wants to know what Ryan thought of her friends. Ryan admits he liked everyone except Brody, who -- he suspects -- was trying to make him jealous and stir up drama for Audrina. When Audrina assures him she's not looking for drama, Ryan tells her he wants their relationship to be more laid back. Hearing this, Audrina takes Kristin's advice -- and asks Ryan whether or not they're exclusive. In response, Ryan admits he hasn't even thought about another girl since they started hanging out.Across town at Falcon, Brody and Kristin are meeting up for a late-night bite. Brody fills Kristin in on the Spencer-Holly drama from Enzo's party, concluding that Spencer's officially "out of his mind." When the subject turns to Audrina, Kristin says she "wouldn't mind" if Brody hooked up with her after all. Of course, now that Audrina and Ryan are dating, there doesn't seem to be much chance of that.Back at Casa de Speidi, Holly and Heidi are talking about The Darlene Incident from Enzo's party. When Spencer pops in, Holly tells him she felt "disrespected" and asks him to refrain from talking about her mom like that, especially in her presence! Instead of apologizing, Spencer explodes again, going off on Darlene ("she's just the vagina who made Heidi") and calling Holly a "liar" and a "poser" before slamming the door on his way out.Stunned, Holly bursts into tears and tells Heidi she's worried that Spencer will drive her out of Heidi's life for good. "He scares me," she admits, choking back sobs. Meanwhile, Heidi admits she's done cleaning up after Spencer's messes. "I'm so sick of all of this," she sighs. "I just don't wanna do this anymore." When Holly leaves, Spencer's still standing outside the house, pacing back and forth in anger. "We're clear you're not welcome here, right!?" he shouts. Holly has two words for him in return: "You're pathetic."