Everyone is on edge as the ladies come together to support Lynne Curtin's private jewelry show. Though both Tamra and Gretchen vow to get along, it doesn't take long for the name-calling and insult-hurling to get under way.
Jeana Keough makes the gut-wrenching decision to pull back from spending so much time with the Housewives in order to concentrate more on her real estate business, which is struggling in a sagging economy; Alexis Bellino joins the cast of the Housewives.
Vicki invites the housewives to a weekend in Florida, but there is tension when Alexis and Tamra invite Jim and Simon. Slade surprises Gretchen by arriving, also causing Vicki to alienate herself from the group.
Lynne confronts Gretchen about overstepping her boundaries with Alexa; Vicki invites all of the housewives to a "girls only" slumber party at her house; Vicki invites a psychic to do readings where Tamra seeks guidance on her relationship with Ryan; The housewives decide to teepee Jeana's house.
Alexis and Tamra grow closer; Gretchen and Slade go to the races with Alexis and Jim; One of Gretchen's friends flirts with Alexis's husband, Jim; Lynne and Frank have trouble with Alexa going out too much.
Marriage woes impact the Barneys and their children. Meanwhile, Gretchen anticipates the premiere of her makeup line. Lynne seeks advice from her mother about her daughters and Alexis decides to host a cooking party where Gretchen criticizes Lynne over her parenting, causing Lynne to break.
Season 5 finale. The housewives prepare to attend the season finale party. Vicki, still hurt by the San Francisco trip, vows to stay clear of drama. Gretchen and Slade color-coordinate outfits, looking (according to Vicki) as the plastic toppers of a wedding cake. Lynn's daughters arrive at the party obviously under the influence, and Lynn excuses herself for knowing stating that the limo was big and she didn't know what her daughter's were up to. Tamra and Simon have a heated argument in the limo on the way to the party, with Tamra stating that she wants a divorce. The show ends with a recap of each housewife as is the tradition, and the last summary is that Tamra and Simon are divorcing.