Susan learns that she is expecting a child while Bree continues to fake her own pregnancy. Gabrielle begins an affair with her ex-husband, Carlos and Lynette tries to conceal her cancer from her friends and children. The episode also introduces Katherine Mayfair, Susan's old friend who returns to the neighborhood after being away for 12 years.

Lynette kicks Tom out of her chemotherapy sessions. Susan is mistaken for a stripper. Bree attempts to steal a prize-winning recipe from Katherine.

Bree informs the housewives of what she overheard in the Mayfair house. Stella makes some special brownies to help Lynette through chemotherapy. Susan throws a charades party for the whole neighborhood.

Bob & Lee's contemporary water sculpture in their front yard prompts the Wisteria Lane neighborhood association into action. Edie finds out about the affair that Carlos is having with Gaby. Also, John Rowland wants to rekindle his romance with Gaby.

This is the show's first Halloween episode. Edie Britt's biggest fear comes true when Carlos walks out on their relationship. Susan finds Mike's father, who was supposedly dead. Danielle goes into labor right in the middle of the Halloween party... and somebody has to deliver the baby.

A mysterious stalker from Adam's past shows up on Wisteria Lane, and they have dinner. Detectives question Gabrielle about Victor's whereabouts. Danielle's baby puts stress on Bree and Orson's marriage. Lynette has a reunion with her long-lost stepfather, Glen. Susan notices Mike is behaving strangely.

A tornado comes to Wisteria Lane, forcing residents into basements, cellars and safe rooms, and destroying homes and lives. Meanwhile, Susan ends up at the hospital after falling down the stairs.

In the aftermath of the tornado, the residents of Wisteria Lane try to rebuild their lives. Katherine discovers someone may know her secret while Lynette faces the possibility of her family's fate.

Two weeks after the tornado, with Mike still in rehab, Mrs. Delfino gets a visit from her cousin Tim. Meanwhile, Bree desperately awaits to return to her own house. Gabrielle learns that Carlos' blindness is permanent. Katherine is unable to keep some of her secrets from the women of Wisteria Lane. Finally, a surprise wedding ceremony has its own share of secrets.

Susan and Mike try to name their son. Lynette is arrested for supposedly attacking Kayla, and Tom must do what he can to save his family. Bree is being stalked by Orson, and when she meets with Reverend Green, the reverend tries to hit on her. In the meantime, Gabrielle is still helping the police trying to detain Ellie for dealing drugs. Finally, Katherine is visited by her ex-husband, Wayne.