Shortly after David Abbott moves into his new San Francisco digs, he has an unwelcome visitor on his hands: winsome Elizabeth Martinson, who asserts that the apartment is hers -- and promptly vanishes. When she starts appearing and disappearing at will, David thinks she's a ghost, while Elizabeth is convinced she's alive.

Carrie, Charlotte, and Miranda are all married now, but they're still up for a little fun in the sun. When Samantha gets the chance to visit one of the most extravagant vacation destinations on the planet and offers to bring them all along, they surmise that a women-only retreat may be the perfect excuse to eschew their responsibilities and remember what life was like before they decided to settle down.