Season four kicks off with tensions nearing a breaking point between Audrina and Lo.

When Lauren runs into Spencer at Stephanie's birthday, the birthday girl finds herself at odds with her brother and her friend.

Lauren begins to realize that the chemistry she felt for Doug in high school may no longer be there.

A blowout trip to Vegas breaks down when Audrina snubs Lauren, Brody brings up Stephanie's past, and the boys end up in jail.

Lauren and Audrina fight to save their friendship, but it might be too late.

Heidi's sister Holly reaches out to Lauren, forcing both Lauren and Heidi to reconsider what happened to their friendship.

Lauren leaves for family vacation, and things in Los Angeles go awry. Stephanie dates Doug behind Lauren's back, and Audrina gets friendly with Heidi.

The truth finally comes out about Stephanie's relationship with Lauren's ex-boyfriend Doug when they all meet up for the first time at Doug's pool party.

Lauren gets a letter of apology from Heidi and realizes there's only one thing keeping them from being friends again.

Audrina reconnects with an old flame Cory and finds herself juggling two guys.

Lauren and Audrina travel to Cabo for Brody's birthday, but when Justin gets jealous of Audrina's new relationship, the party turns into a fight.

Lauren tries to make peace between Brody and Stephanie.

Audrina gets her own place, hoping Justin will move in with her but everyone fears she is moving for the wrong reason.

Whitney travels to New York expecting to reconnect with Alex, but a new boy named Jay steals her away.

Lauren lets Heidi's sister crash at her place.

A rumor about Lauren and Justin threatens to ruin Lauren and Audrina's friendship for good.

Audrina tries to save her friendship with Lauren after accusing her of hooking up with Justin.Â

Whitney gets offered a chance at her dream job in her New York, and hopes to see Jay while she's there.

Spencer and Heidi ignore the concerns of their families and runaway to Mexico to elope.

When Lauren and Heidi have a run-in, they put their feud aside and remember why they used to be friends.