The third season premieres with Lauren and Heidi still unable to get past their differences and having become mortal enemies. Meanwhile, Whitney has graduated from college and is now juggling a real job and Audrina has become Lauren's new roommate and best friend.

Lauren returns to Laguna Beach for some advice. Meanwhile, Audrina and her new beau get serious with their relationship and Spencer proposes to Heidi.

Audrina invites Lauren out to dinner to get to know Justin better. Lauren is not impressed by him. Audrina talks to Justin and decides to give their relationship time. Spencer suprises Heidi by buying two arcade games for the apartment. Later, she suprises him by painting over the mural in the living room.

Spencer and Heidi go away for the weekend to meet Heidi's parents, causing Spencer to flake on his and Brody's barbeque. Lauren, Audrina, Lo, and Justin Bobby attend. Justin Bobby flirts with other girls and leaves Audrina at the party, and Lauren finally realizes that she and Heidi will never be friends again.

Just when everyone believes that Justin Bobby is finally history, Audrina decides to rekindle the relationship, much to Lauren and Lo's surprise.

Lauren is still wondering who could be the guy for her when suddenly Jason gives her a call and wants to catch up.

Brody celebrates his birthday in Las Vegas and of course Lauren and her friends are invited too. Meanwhile Heidi has to face more problems at work than she likes.

When Jen wants to be friends again with Lauren, however the dark past starts to haunt everyone. And not everyone likes the past revealed.

The Young Hollywood party finally happens and Whitney is in charge. Heidi celebrates her 21th birthday with Spencer. And Audrina might have a new admirer.

Lauren and Whitney have to cover an event for Teen Vogue, where Lauren runs into Heidi and of course they fight again. Later on Heidi tries to make up to Lauren, but Lauren turns her down. Meanwhile Audrina and Justin still struggle in their undefined relationship.

Lauren and Audrina find out that Spencer has a sister. She also pays Spencer and Heidi a visit. When Lauren and Audrina hang out with Brody, they not only run into Spencer's sister, but also run into Justin - with another girl.

Lauren and Lo are looking into the real estate market as they plan to buy a house. Meanwhile, Audrina reconsiders her situation as a single woman.

The girls go out to find a new home. When they find one, the guest list for the housewarming party is subject to more than just one fight.

While Lo and Lauren enjoy living at the house, Audrina feels more and more left out. Meanwhile Stephanie thinks it's time to get rid of Spencer and Heidi prepares her next step in her career.

Lauren tries to uphold her friendship to Audrina, but is it already too late? Meanwhile Spencer tries to win Heidi back and risks her career to do so.

The tension between Lo, Lauren and Audrina continues and soon things reach boiling point.

Brody attacks Stephanie and insults her, just before he's arrested.

Brody is still in jail, so the girls try to come up with a way to get him out. Plus Audrina and Lauren finally sit down and talk to each other.

Justin goes MIA. Holly calls Lauren, but how will Heidi and Spencer react to that?

When Lauren is away for a couple of days, Stephanie and Doug start dating secretly. How long will that stay a secret though?

Doug and Stephanie have to explain themselves to Lauren. Meanwhile Heidi's mother pays a visit.

Heidi tries to reach out to Lauren. Meanwhile Audrina has a date, but what will Justin say to that?

Spencer sets an ultimatum for Holly to move out. Meanwhile Audrina checks which boy is best for her. Will it be Justin?

Lauren and Audrina travel to Cabo for Brody's birthday, but Audrina's problems with Justin threaten to ruin the festivities. Back in LA, Spencer gives Stephanie's new boyfriend a hard time over dinner.

Audrina wants to make things work with Corey, but finds herself torn when Justin drops by Epic. Meanwhile, Stephanie starts having doubts about her new boyfriend when he fails to defend her in front of Brody.

Audrina suprises Lauren when she moves out, and Heidi disappoints Brent Bolthouse when she invites Spencer to a work event and gets caught having a little too much fun.

Heidi decides to go back to Brent and Sam and ask for her job back. Plus, Holly Montag's crashing at Lauren and Lo's since getting kicked out of her sister's place.

A nasty rumor threatens to end Lauren and Audrina's friendship and Heidi realizes Spencer's been withholding information from her.

Spencer and Heidi ignore the concerns of their families and elope in Mexico. Meanwhile, Whitney says goodbye to Lauren and her life in Los Angeles as she leaves for her dream job in New York City.

The season four finale finds Lauren and Heidi running into each other and are reminded why the once were best friends. Meanwhile, as Heidi's mom pays a visit, the she and Spencer know they must face reality; and Audrina is surprised by Justin with a trip to Palm Springs.

As Audrina tries to get over Justin, she sees Brody in a new light. Plus, Heidi drags Spencer to couples' therapy and Stephanie has a hard time handling work at People's Revolution.

Lauren is put into an awkward situation after Stephanie messes up at work. Meanwhile, Justin calls out Audrina for hooking up with Brody.

Heidi and Spencer head down the aisle and two unexpected guests manage to attend the ceremony.

Kristin makes a big first impression in The Hills when she gets in a fight with two different women over one guy, works her way to queen bee status and lands a hot date with a motorcycle all in one episode.

Kristin kicks her pursuit of Justin into high gear after Audrina blows her off, while Heidi and Spencer's opposing views on kids causes trouble.

Justin doesn't show up at Brody's party and Audrina has a new target.

Justin tries to make up with Kristin. Heidi thinks something is wrong with Holly.

Heidi and Stephanie sit Holly down for an intervention when she continues drinking. Plus, Kristin gets upset with Justin's head games and Brody and Jayde get into a fight that leads them to reconsider their relationship.

Justin finds himself in hot water after Kristin and Audrina meet. Heidi wants to have a baby, but Spencer has another plan.

Audrina gets her heart broken when Justin ends things for good, it's a war of the exes over Brody, and Spencer considers drastic measures to stop Heidi's baby obsession.

While on a lunch date, Kristin and Brody recall the crazy times they used to have together. After Brody toasts to having a nice lunch without fighting, Kristin mentions that Jayde wants to talk with her. Brody tells Kristin she's out of her mind ...

Kristin and Stacie's girls' weekend in Vegas becomes a threesome when Justin joins the fun. Plus, Spencer panics when he uncovers Heidi's pregnancy scheme.

Kristin is in Malibu packing up her beach house when she tells Stacie she doesn't want to pursue a relationship with Justin Bobby. Kristin says things were perfect when they were in Vegas, but she knows real life isn't like vacation.

Kristin has a hard time moving on from Brody. Audrina bumps in to Justin and starts to have doubts about her relationship with Ryan.

When Justin Bobby shows up onstage at a show Audrina, Steph and Lo are at, all the girls are surprised.

It's Audrina's birthday and the gang, including Justin, board a boat at Marina Del Ray to celebrate. Elsewhere, Kristin has another run in with Allie at a club where a fight erupts. Also Audrina breaks up with Ryan and Kristin warns McKaela to stay away from her.

The gang heads to Costa Rica for a group surf trip, and Brody gets jealous when Kristin hooks up with a local bartender. Meanwhile, Audrina fights her attraction to Justin, and Stephanie finds herself at odds with the jungle environment