When the Hills gang lands in Costa Rica, Kristin predicts sparks will fly between Audrina and Justin. Despite the romantic beaches, however, Audrina insists she is not looking for love. Meanwhile, Frankie has his eye on another on-again, off-again couple: Kristin and Brody! But will these flirtatious exes end up getting back together -- or grow farther apart?Kristin and Stacie start out their trip with a dip in the ocean at Santa Teresa beach. While working on their tan, they discuss Audrina and Justin's rocky history ("that hasn't really been a good situation," Stacie observes) and a frustrated Kristin admits she wants a relationship with Brody. Tired of waiting for him to settle down, Kristin decides she is ready to play the field -- starting with the boys in Costa Rica!That night, the group meets for drinks at the Florblanca resort. Justin makes Audrina uncomfortable when he tells her she looks "cute," while Kristin tries to make Brody jealous by flirting with the bartender, Will. Instead of getting angry, however, Brody tells Kristin to go for it, saying she is like his "little sister" and explaining that he is "looking for chicks, too." Furious, Kristin storms off while Audrina complains about Justin getting a little too touchy-feely at the bar.Minutes later, Kristin meets Stacie and Taylor (Brody's friend) at the poolside to dis-cuss Brody's 'you're-like-a-sister' remark. Taylor tries to calm her down, while Kristin confesses a part of her was still hoping something would happen between them. Tired of venting, she heads back to the bar and makes a date with Will for later that night.After finishing his shift at the bar, Will takes Kristin (and the rest of the group) to Day & Night Beach Club for a late night dance party. Despite some bad weather, Kristin and Will continue to laugh, dance and have a good time in the rain while Brody glowers from the sidelines.At the resort the next day, Kristin denies having strong feelings for "the bartender" (though Stacie reminds her she has another date with him tonight!). Meanwhile, Audrina confesses that things are "weird" between her and Justin. "I feel like I don't know him anymore," she tells the group, adding that they're "friendly" but not friends.Over at Santa Teresa Beach, the guys take a break from surfing to talk about Au-drina. Frankie tells Justin he should go for it, but Justin insists she has "baggage" and says he is giving her space. Taylor mentions his heart-to-heart with Kristin and hints that she is looking for a relationship, not a fling. "If she has a chance to get back together with you," he tells Brody, "she'd take it in a second." Meanwhile, Kristin tells the girls she is done waiting for Brody to come around. "If he gives me any s---," she warns, "I'm just gonna hang out with Will all night."That night, Will joins the group for dinner at Florblanca while Audrina tells Justin she felt uncomfortable the night before. Justin admits he doesn't know how to act around her now that they're just friends, but Audrina explains that she is not looking to start anything back up again. "We're friends now," she tells him, firmly. "It's not like that."Meanwhile, Brody tells Kristin he doesn't want to see her get hurt by Will. "You're like my little sister," he explains, "I want you to be happy." When he follows this up with a toast (to "my sister who I've had sex with"), Kristin decides she has heard enough, and pulls Will aside for a private make-out session on the beach.The next day, the gang spends their final morning in Costa Rica together hiking down to a waterfall. Unfortunately, things aren't quite so picturesque when they get to the airport. While waiting for the plane, Kristin taunts Brody by saying she might come back to visit Will, while Audrina pointedly tells Justin she isn't looking for romance. Looks like it's gonna be a bumpy flight home...!