Carrie finds out that her building is going co-op and she has to move. Aidan offers to buy her apartment and move in with her. Carrie finds herself both tempted and scared about the idea of sharing her space on a permanent basis. She's even more alarmed when while rummaging through Aidan's clothes she lands upon an engagement ring. It's creates such an internal upheaval, she runs to the kitchen sink and vomits. Carrie tells the girls about her reaction and voices her fears that it's too fast ? and that to boot, the ring is not at all her style. Miranda admits that she had helped Aidan select the ring. Carrie nervously waits for Aidan to pop the question and wonders: How do you know when it's right?

Meanwhile, Samantha has a drink with her new client, Richard Wright. He proudly tells her that he enjoys sleeping around and is not at all interested in marriage, piquing single-girl Samantha's interest. Their next encounter finds them in Richard's private jet headed for the mile-high club.

Miranda tells Steve that she's carrying his baby and is going to keep it. Steve is shocked, especially when Miranda tells him she's going to take care of the baby herself. Meanwhile, fertility challenged Charlotte starts taking hormones and learning Chinese in case they need to adopt a Mandarin baby.

Carrie runs into Big and tells him that Aidan wants to marry her. Big tells her that Aidan's not the man for her and that she's not the marrying kind. Carrie replies that she's just not ready.

At the annual Highland Fling, Bunny tells Charlotte that a Mandarin child is out of the question for the MacDougal clan. Charlotte screams at Trey and rushes home. Later, when Charlotte asks Trey for her hormone injection, Trey admits that he is having second thoughts about having a baby. He says he doesn't want to try anymore and wants it to be just the two of them.

Aidan proposes to Carrie as they take Pete for his nightly walk. The ring he gives her isn't the one Carrie had spotted; it's beautiful. After Aidan tells her he wants to spend the rest of his life with her, Carrie takes a deep breath and says yes.

Across town, Miranda opens her door to Steve who is holding out an engagement ring. Miranda tells him he's crazy and they both agree they don't want to marry each other. They decide they'll figure things out.

Carrie tells Samantha she's engaged and shows off her ring. Samantha orders them a drink and tells her that she picked the ring out with Aidan.

It's Saturday night and Carrie is raring to go out on the town, but Aidan would prefer to stay home with a bucket of KFC. So, Carrie invites the girls to go out dancing at a hot gay club. At the club, Charlotte runs into Anthony and his friend who works for House and Garden magazine and they dance the night away. Carrie makes friends with a cute gay boy named Oliver at the bar. Miranda runs into Max, a junior associate at her firm. He asks her not to tell the partners he's gay and she asks him not to tell them she's pregnant. When Carrie gets home she's ready for some action but Aidan wants to sleep. Samantha, who took Ecstasy at the club, has X-cellent sex with Richard and ends up declaring her love for him.

Carrie has lunch with her new gay date Oliver. She wonders: To be in a couple, do you have to put your single self on a shelf?

At work, Miranda finds out Max has spilled the beans on her being with child; she then lets it slip that he's gay. They both realize it's time to stop hiding their personal lives. Charlotte finds out that House and Garden wants to shoot her apartment, but Trey doesn't want to do it. He abruptly tells her that she can have the apartment and that he'll move back in with his mother.

Samantha talks to Richard about that thing I said the other night. Richard says it doesn't matter, he's knows she was on Ecstasy. Samantha realizes that she secretly wished it did matter to him.

Carrie gets ready for another fabulous night out with Oliver and puts her engagement ring on a chain around her neck. Aidan offers to go, but she convinces him not to. At the club, Oliver flirts with men and Carrie starts to wonder what she's doing there. She realizes she wants to be with Aidan and heads for home.

As Charlotte prepares for the House and Garden photo shoot, Trey shows up. He tells her that he wants to at least do that for her. They pose as the happy married couple they no longer are.