While Audrina, Lo and Stephanie are out to lunch, talk turns to Kristin when Lo mentions that Kristin was invited to Heidi and Spencer's "welcome back party." Audrina asks Lo for some background on Kristin's "man-eater" reputation. Lo discloses Kristin's high school dramas. "She is not afraid to get in your face, not afraid to stand up for herself and if you're on her bad side it gets really nasty," Lo warned. Audrina recalled that Kristin once slapped Lauren outside of a club. Lo wonders aloud if Kristin will be their friend now, while Audrina says she'll give her benefit of the doubt.Over at Brody's condo, Kristin is on Jayde's mind. She is taking a long time to get ready for Heidi and Spencer's bash because she doesn't want to go meet Kristin, who is Brody's ex-girlfriend. Brody assures her that there's a reason why they broke up after seven or eight months, but when Jayde presses for details about the breakup, he chalks it up to being young. Jayde is still curious about Kristin, and Brody tells his worried girlfriend, "[Kristin] is cool. You've got to watch out for her, but she's cool."Kristin makes her way the party, which is at full swing in Hollywood at the London Hotel. Things get uncomfortable for Audrina when Justin shows up but doesn't say hi to her. When Kristin finally gets to the party she receives a big welcome from all the men -- including Justin. And Audrina is bothered that Kristin made a beeline for him. "It's girl code. You just don't go there."Stephanie sticks up for Audrina by telling Justin that he needs to respect Audrina. Justin insists that he and Audrina are on cool terms and that it's time for them to move on. Kristin interrupts to tell Stephanie to back off Justin and takes offense. "He needs to respect Audrina, like I'm doing something?" she asks. Audrina comes over after hearing her name and Kristin gets heated, saying she was just trying to talk to her friends and got attacked. Stephanie tries to intervene when Kristin gets in Audrina's face and dares her to get physical, but Kristin tells her to quit getting in everyone's business. Kristin continues shouting after Audrina and Stephanie as they walk away. "If it's going to be like this it's...on, bitch!" Kristin warns.The next day, Audrina and Stephanie talk about their run-in with Kristin. Audrina says, "after [Kristin] being a complete psycho-bitch, that's it. I do not like her." Audrina says Kristin is a bigger threat to Jayde than she is when it comes to Brody. Stephanie invites Audrina to Frankie's birthday party the next day, but Audrina declines when she finds out Kristin will be there.Meanwhile, Spencer and Heidi are house-hunting for a rental. They visit a quaint, tree-lined home in the suburbs first. Heidi immediately falls in love with the abode, but Spencer is turned off when the realtor mentions a room that could be turned into a nursery.At Frankie's party, Stephanie is offended when Kristin ignores her. Instead, Kristin talks to Justin. "How single is single?" she asks him. Justin claims that aside from Audrina he's been single for four years. Justin tells Kristin that he and Audrina were never "fully together." Lo and Stephanie raise some eyebrows when they see the flirtation heating up between him and Kristin. Still, Lo says she will be nice to Kristin because she doesn't want to get on her bad side. Eventually, Kristin and Justin talk about going on a date. When Kristin asks him how Audrina will feel, Justin tells her not to go on a date with him out of spite.Spencer takes Heidi to another house for rent. Heidi feels this second place is too "Hollywood party house" and prefers a cozy house in the suburbs. Spencer tries to get her to warm up to the modern home, but Heidi insists that the house is too cold and the last thing she wants. When Spencer tells Heidi he already put down a deposit for the pad, she is not happy. "We got married to decide things together," Heidi says. Spencer responds, "It's my way or the lame way."Later, Lo and Stephanie go to Audrina's house to catch up. They tell Audrina about what happened with Justin and Kristin at Frankie's birthday dinner. "[Kristin] has to realize that these are people's lives she's messing with and people do have hearts and feelings," Audrina says. Audrina looks upset when Stephanie tells her that Kristin probably went home with Justin after the party.Meanwhile, Kristin and Justin meet for dinner. Kristin tells Justin that she almost didn't come because Audrina seems to still have feelings for him. Kristin says she understands where Audrina is coming from because she's been in a position where it seemed like someone was trying to steal her love interest. Justin makes it clear that he and Audrina were never exclusive, but Kristin insists that Audrina will always have a thing for him because he's the guy she couldn't get. The conversation quickly turns to Kristin and her interests. And as the two get acquainted, the flirty banter increases, culminating in a proposition to break in Kristin's bed. "You're evil," Justin says to her. Kristin fires back, "I knew what I was getting myself into."