The episode starts with Carol (Ross's ex-wife) and Susan (her lesbian life partner) picking up Ben from Ross. Just before they leave, they make an announcement - they're getting married. Ross has a lot of difficulty with this and decides not to go.
Rachel's mom comes to visit, and announces that she is divorcing Rachel's father, because she admires Rachel's life so much. This leads to her doing increasingly wild things, such as flirting with other women and suggesting to smoke pot.
Phoebe's massage client dies on her table, and as she was cleansing her aura when she died, Phoebe believes that the spirit of an 82 year old woman is living inside her. The woman's husband tells Phoebe that his wife wanted to see everything before she died. Phoebe spends the next day touring New York.
Carol and Susan's wedding caterer has a mountain bike accident, so they ask the unemployed Monica to do it. Monica plans and plans it all out, but then doesn't leave enough time to actually do it, so she makes everyone else miserable while helping cook.
Carol arrives at the apartment and tells Ross that the wedding is off, because her parents decided not to come. Despite his personal problems, Ross convinces Carol to go ahead with it.
The episode ends with Carol and Susan tying the knot, Ross giving Carol away, Rachel getting drunk because of her mother, the spirit leaving Phoebes body because shes seen everything - a lesbian wedding and Joey and Chandler feeling depressed because there are so many women at the wedding, yet they can't ask any of them out. (Joey: I feel like Superman without my powers. I have the cape - yet I cannot fly)