As soon as things start to feel settled in 'The Hills', something comes along to shake everything up. After a rollercoaster engagement to Spencer, Heidi called it off and headed to Colorado. And, just when Lauren and Brody were starting to figure things out, Lauren went to Paris for the Crillon Ball. Now, Paris is about to change everything...Touching down in Paris, Lauren and Whitney are greeted by a chauffer, who hands them an itinerary. First things first -- they need to pick up their ball gowns and the shoes for the debutantes who'll be making their debut at the Crillon Ball.Meanwhile, Heidi's hitting the slopes in Crested Butte, Colo., with her mom. For Heidi, the retreat has been a breath of fresh air and a way for her to gain clarity on the whole engagement fiasco. She decides that if Spencer really wants what's best for her, he's going to have to give her time and space.In Paris, Lauren and Whitney head to the Alberta Ferretti store, where they pick up their gorgeous ball gowns. Then there's just one last stop before they head to the hotel -- they must pick up the debutantes' shoes at Colette. When they arrive, though, the store is closed. Uh oh!Back in 'The Hills', Spencer's little sister, Stephanie, pays Spencer a visit. He tells her that Heidi high-tailed it out of there after their last fight -- but he's already come up with a plan to win Heidi back. He's going to chase her down in Colorado and get to the root of the problem. But Stephanie isn't stoked on the idea; she thinks he should give his girl some space.The next morning, Lauren and Whitney receive their itinerary for the day, saying they're expected at the Teen Vogue photo shoot -- with the debutantes' shoes! Looks like they have to head back to Colette ASAP!Later, the Montags receive an unwelcome surprise when Spencer rolls into their sleepy Colorado town unannounced. Heidi's father is none too pleased when Spencer strolls up to the house uninvited. Spencer pleads his case, saying he only showed up in person because Heidi wasn't answering her phone. Heidi's dad reluctantly shows him inside to wait for Heidi.Meanwhile, at the Teen Vogue photo shoot, Lauren and Whitney are greeted by senior editor Kimball. Assigning the girls duties, Kimball sends Lauren to hair and makeup and tells Whitney be his "eyes and ears" by asking questions and getting quotes from the debutantes.During the photo shoot, Lauren receives a phone call from Audrina, who just got home from Les Deux. Audrina bumped into Brody and Frankie -- and Brody was snuggling up to a new girl ... who he's calling his girlfriend. Lauren's shocked. It only took him two days to replace her?!Arriving home from the slopes, Heidi finds Spencer on the couch with a dozen roses. Spencer says he made the trek because he wanted to apologize, but Heidi has nothing to say to him.Excited to be in Paris, Lauren and Whitney decide to meet up with the band Rock&Roll, who Audrina introduced them to back in L.A. When the girls arrive, guitarist Matthias shows immediate interest in Lauren. After learning she hasn't seen the Eiffel Tower yet, he offers to take her there. Under the city landmark, they celebrate her time in Paris by popping open a bottle of champagne.The next night, Lauren brushes up on her French by finding words to describe Brody ... like "scum." As soon as she says she needs a "rebound," the guys from Rock&Roll text her, inviting her and Whitney out for a fancy night out on the town. Lauren doesn't have anything to wear, so she decides to stitch up the hem on her ball gown. Whitney thinks it's a recipe for disaster, but Lauren assures her that she's successfully done it before.Stateside, Spencer's still struggling to win Heidi over. During an awkward dinner, Heidi toasts her "amazing" parents while giving Spencer an icy glare. Instead of lavishing praise on him next, she asks if he's planning on staying long.When the temperature rises, Heidi's mom steps in, telling Spencer that Heidi needs some time to herself. Defensive, Spencer says he and Heidi didn't have any problems until he popped the question. Steaming, Heidi says their trouble stems from Spencer storming out on her... twice. Spencer calls her a hypocrite for running off to Colorado after an argument, but Heidi doesn't see it that way.In her adjusted ball gown, Lauren meets the Rock&Roll boys with Whitney. When a debutante escort shows up, Matthias becomes jealous. Jumping right to the point, Matthias asks Lauren if she's dating anyone. Lauren pointedly says she's single and admits she's sad she's leaving Paris so soon.When the girls realize it's getting late, they decide to leave. Matthias chases them, asking how come Lauren left without giving him a kiss. After a European double-cheeker, Matthias says they should all meet up again before the girls head back to 'The Hills'.Getting ready for the Crillon Ball, Lauren undoes the hem on her dress. As she finishes removing the stitches, she notices a big brown spot on the front -- and back! It looks like a coffee stain, but Lauren swears she was really careful. Then she realizes she left the curling iron on when she put the dress down, causing a big burn on her Alberta Ferretti gown!As Lauren tears up, Whitney figures out a solution to the setback. She calls the store and secures a new dress. The girls race out of the hotel to pick up the new dress with an hour to spare.Out to dinner in Colorado, Heidi asks Spencer when he's leaving. The two are obviously on different pages, leading Heidi to think they've been fighting about more than just the wedding. She thinks they rushed into their relationship too quickly, putting too much pressure on them. Getting snippy, Spencer wonders why she doesn't just break up with him. Taking his words to heart, she tells him that when she returns to L.A., she wants him out of their apartment.On the night of the Crillon Ball, Whitney and Lauren are fully glammed out. Kimball asks Whitney to help identify the debutantes and their dresses as they walk into the room while Lauren takes photos. When they're finished, Kimball sends Lauren off on an errand and grabs a minute with Whitney. He tells Whitney that she doesn't seem that into her job, and she admits she wants to be more hands-on when it comes to fashion. Kimball suggests she pursue her dream rather than staying at Teen Vogue.With the Crillon Ball in full swing, Lauren gets a call from Matthieu. He wants to take her for a late-night tour on her last night in Paris. Lauren thinks it's the opportunity of a lifetime. But when he pulls up on his Vespa, she's not quite sure how to handle the dress situation. Stuffing her gown underneath her legs, she takes off on a ride that leaves the city whipping past her.In Colorado, Heidi walks Spencer to his car, where they decide it's best for them to go their separate ways for now. Looks like Crested Butte isn't the only thing that's frozen over this winter!When Whitney catches up with Lauren the next morning, Lauren relives her Vespa experience. When questioned about Brody, Lauren has no response. They knew Paris would change their lives, and Lauren indeed has a new perspective on things. The same goes for Whitney, who's decided she wants to leave her job at Teen Vogue.After a week in Paris, Lauren and Whitney head back to 'The Hills'-- and reality.