Sabrina, Joan and Melissa’s long time assistant, is having her twenty-year wedding anniversary and wants to renew her vows. Since Joan is already performing in Las Vegas that week, she offers to fly the entire family out to celebrate the event together. The girls decide to wear the same dresses they wore to the original wedding 20 years ago. Melissa tries on her own wedding dress, which gets Joan thinking it would be great to get Melissa a new man in her life – especially after the grief Jason put her through. 

Upon arriving in Vegas, Lynne plays a joke on fellow comic Tony, telling him that she’s opening for Joan, which makes him insanely jealous. Joan agrees to play along with Lynne’s lie, but only if Lynne sets Melissa up on a date.

After Joan’s sold-out show (where Tony learns that Joan was kidding him about Lynne opening for her), the girls have a wild bachelorette party. Joan naturally leads the charge, and a drunk Lynne admits to Melissa that Joan was behind the blind date. The next morning,

Joan and Melissa take a Gondola ride. Melissa confronts her mother about setting her up, and Joan argues that she only wants to see her daughter happy. Melissa announces that she doesn’t need to be with someone to be happy and that it doesn’t mean the end of her fertility plans. Hearing that Melissa still wants to have a baby, Joan starts working out all of the logistics right there in the boat. Melissa’s sorry she brought it up.

Finally, it’s time for the wedding. The girls struggle to squeeze into their 20-year old dresses. The wedding is gorgeous. Joan walks Sabrina down the aisle and is moved watching Sabrina and her husband renew their vows. At the reception, Joan and Melissa give touching speeches about their friend Sabrina, and Tony and Lynne officially end their feud after wrestling over the bouquet toss. It’s an old-fashioned love fest as the family enjoys quality time with each other after what has been a difficult yet thoroughly entertaining year.