Lizzie and Sam get a surprise visit from Sienna. Operating on the premise that men can't resist a woman who is "taken," they masquerade as Lizzie's bachelorette party and go on the prowl. Lizzie lets Marco pick her up, and takes him back to her place for one last fling. Sienna learns of Sam's interest in Richard and Jason, and insists that they attack the easier target -- Jason. They hack into his e-mail to find out where he will be, then follow him and his date, Lulu, to a movie theatre. When the film ends, Sienna creates a distraction, but Sam is unable to pry Jason away from Lulu. She and Sienna follow them to Jason's apartment building and spy through the window as they have sex. Lizzie tells Marco she's not engaged; he tells her he's married. Sienna says farewell to her friends and returns to the suburbs. Sam thinks her marriage is in trouble due to all her silly rules. She decides to get out of Jason's way and arranges to bump into Lulu to tell her what good man she's found. Sam feels pretty good about doing the right thing, but Lulu is appalled at the thought of dating a nice guy, and ditches Jason.

It's just another boring Sunday until Sienna breezes into the dive bar and announces she's staying until her husband apologizes for reading in the bathroom. She decides to show her protégés how to get a man's attention and gets aggressive with a Muscle-Bound Dude sitting at the bar. He's a cop, and he arrests her. Sam is sobered by the incident and thinks that Sienna's rules are guaranteed to keep them alone. She's ready for a change and asks co-worker Kate about her new boyfriend, Shermann. He's a public defender, and agrees to pull a few strings to try to get Sienna released. Sienna's husband, Nathaniel, visits her in jail. She apologizes, he forgives her, and she vows to try to stop sabotaging their relationship. Kate tells Shermann about her 10-date rule, and he suggests they have all 10 dates in one day; at day's end, they can then have sex within her rule. Sam types up all of Sienna's rules and shows Lizzie the ones she questions. Lizzie is reluctant to give up any of them. Sienna is released and bumps into the Muscle-Bound Dude at the desk. He talked to Nathaniel and has agreed to drop the charges. Nathaniel awaits Sienna in the jail's visiting room, where they have sex.