Lauren is thrown a surprise birthday party in the Season 5 opener, and she's none-too-pleased when Stephanie brings Heidi along.
Heidi heads home to Colorado to cope with Spencer's flirtatious ways. Meanwhile, Spencer and Brody put an end to their feud.
Heidi blows up at Spencer when she catches him hanging out with Stacie the bartender. Meanwhile, Lauren puts her reputation on the line when she gets Stephanie an interview with Kelly Cutrone.
Heidi and a reluctant Spencer begin couples therapy; Stephanie starts working at People's Revolution.
The ladies decide to crash the guys' Hawaiian vacation, and sparks fly between Audrina and Brody. Back in L.A., Heidi's ex, Colby, comes to town, much to Spencer's chagrin.
The gang returns to L.A., and Brody and Audrina deal with the fallout from their Hawaiian hookup. Elsewhere, Heidi confronts Stacie yet again after intercepting a text message she sent to Spencer.
Stephanie messes up at work, putting Lauren in an awkward situation. Also: Justin calls Audrina out for hooking up with Brody.
Heidi's father visits, and Spencer has an important question to ask him. Meanwhile, Lauren must fire Stephanie from People's Revolution.
At Heidi's request, Spencer tries to make amends with Lauren in hopes that she'll come to their wedding. Elsewhere, the recently fired Stephanie has a run-in with former boss Kelly Cutrone.
Lauren Conrad says good-bye to "The Hills" in the Season 5 finale. Meanwhile, Spencer and Heidi tie the knot in their long-awaited nuptials, and Kristin Cavallari, Lauren's former "Laguna Beach" rival, makes her grand re-entrance.
"Laguna Beach" alum Kristin Cavallari joins the cast and stirs up trouble when she hits on Audrina's ex, Justin. Elsewhere, newlyweds Heidi and Spencer go house hunting.
Kristin decides to pursue her crush on Justin after being stood up by Audrina. Meanwhile, Heidi offers to babysit her neighbor's kid, but Spencer wants nothing to do with the little one.
Justin makes plans with Kristin, but never shows; Jayde throws Brody a surprise birthday party; Audrina goes on a date with Justin's best friend.
Heidi worries that her sister Holly has a drinking problem after she loses control at a Bolthouse event. Elsewhere, Justin tries to make amends to Kristin by cooking her dinner, but he's still not sure he's over Audrina.
Justin tries to play hard to get with Kristin, but his plan backfires; Holly continues to drink, leading Heidi and Stephanie to stage an intervention; Brody and Jayde have another fight that has him questioning his relationship.
Justin lands in hot water after Audrina and Kristin meet face-to-face. Meanwhile, it's Heidi's birthday, and all she wants is a baby, but Spencer has other ideas.
Now that they're both single, Brody and Kristin consider rekindling the flame. Meanwhile, Audrina meets with Justin to talk about their future, but the conversation doesn't end the way she hoped. And Spencer considers drastic measures to end Heidi's baby obsession.
Jayde clashes with Kristin after deciding she wants Brody back; Heidi hatches a plan to get pregnant---with or without Spencer's consent; Audrina deals with the fact that Justin still has feelings for Kristin.
Justin follows Kristin to Las Vegas, hoping to make amends for his past behavior. Back in L.A., Spencer knows Heidi's up to something and tries to find out what it is.
In the Season 5 finale, Justin wants to take his relationship with Kristin to the next level, but she's still not sure she can trust him. Meanwhile, Spencer confronts Heidi about her sneaky ways.