|#1||Now You Know|
The residents are shocked to learn about Edie's attempted suicide. Susan finds out she's pregnant. Lynette tells the other housewives about her cancer. Bree desperately tries to hide the fact that her pregnancy is fake. Gabrielle continues her secret affair with Carlos. The new residents of Wisteria Lane include Katherine Mayfair, an old friend of Susan's, as well as her second husband Adam, a gyneologist, and their teenage daughter Dylan, all of whom have dark secrets of their own.
|#2||Smiles of a Summer Night|
Susan is mistaken for a stripper. Lynette bans Tom from her chemotherapy sessions. Bree does some sneaky sleuthing in Katherine's house and overhears Katherine and Dylan arguing about Dylan's birthfather. Edie blackmails Carlos into getting engaged. Gabby reveals a shock from the past to Lynette.
Susan and Mike have a charades party at their house. Stella makes some pot-laced brownies for Lynette to rid her of the chemo side effects. Bree tells the other housewives about what she overheard in Katherine's house. Gabrielle is unhappy to learn about Carlos and Edie's engagement.
|#4||If There's Anything I Can't Stand|
Susan unsuccessfully tries to get along with the new gay couple, Bob and Lee, on the block. Tom and Lynette try to spice up their sex life. Rex's mother, Phyllis, returns and discovers that Bree's pregnancy is fake. Edie is diagnosed with crabs.
|#5||Art Isn't Easy|
John Rowland comes back into Gabby's life. Lynette runs against Katherine for Wisteria Lane's homeowner's association. Bree convinces Danielle to let her raise the baby as her own. Edie hires a man to follow Carlos.
|#6||Now I Know, Don't Be Scared|
Susan finds out that Mike's father, Nick, isn't really dead but in prison for murder. Lynette finds out she's been cured of her cancer. Danielle gives birth to a baby boy, named Benjamin, and Bree pretends that it's hers. Gabby is upset that Carlos hid money from her while they were getting divorced. Carlos dumps Edie. Gabby tells Victor that she's leaving him.
|#7||You Can't Judge a Book By Its Cover|
Bree tells Susan that Mike has a drug problem. Stella leaves after learning none of her daughters want her to live with them. Bree gets her grandson, Benjamin, circumcised despite Orson's objections. The question of Victor's survival becomes a cliffhanger after Gabby knocks him off his boat.
Adam's surprised by a stalker from his past. Susan spies on Julie as Julie kisses her tattooed boyfriend. Detectives questions Gabrielle about Victor. Lynette's reunited with her stepfather Glen. Bree and Orson face marital problems.
A tornado tears through Wisteria Lane. Susan tells Mike that if he doesn't get help for his drug problem she will leave him. Bree learns the truth about why Adam and Katherine left Chicago. After trying to kill Carlos, Victor dies in the tornado. Lynette fears for the lives of her family, after Mrs. McCluskey's house is destroyed while her family was inside.
|#10||Welcome to Kanagawa|
Lynette finds out that Ida Greenberg sacrificed her life to save her children. Adam leaves Katherine when he finds out about her past. Bree tries to secure the services of a gay contractor by 'pimping out' her son Andrew while staying with Susan, who schemes to make Bree stay longer. Gabby discovers she will not inherit any money from Victor's will.
Two weeks after the tornado, Mike is about to finish rehab. Gabrielle learns from Edie that Carlos's blindness is permanent. Susan's hunky young male cousin reveals more than expected. A surprise wedding ceremony has its share of secrets.
|#12||In Buddy's Eyes|
Gabby struggles with the reality of having a blind husband, Lynette is surprised when someone from her past (Rick) shows up at Scavo pizzeria. Bree and Katherine join forces to plan the Founders Day Ball.
|#13||Hello, Little Girl|
Bree and Katherine decide to start a catering business together. Lynette tries to deny her feelings for Rick, and Mike learns the truth about his nearly fatal accident.
Lynette finds out who was responsible for starting the fire at Rick's restaurant: the twins Porter and Preston, but learns that Kayla was the one who inspired them to do so. Bree gives Orson an ultimatum to turn himself in for running over Mike. Orson refuses and moves out, but the man-hungry Edie is, as always, there to make the moves onto him. Elsewhere, Susan reconnects with her ex-husband, Karl, at a Lamaze class. Katherine finally finds out that Dylan is secretly meeting with her ex-husband Wayne.
Adele Delfino, Susan's Southern belle, overbearing mother-in-law, arrives for a visit. Carlos and Gabby find out their tenant, Ellie, has a dark secret of selling drugs, and worse still, the police want their cooperation to arrest Ellie. A full scale war erupts between Bree and Edie in which Edie resorts to drastic measures after she learns the secret about Bree's baby Benjamin from Orson. Elsewhere, Tom persuades Lynette to give Kayla a second chance... which Lynette soon regrets. Also, Katherine is hiding an even darker secret when she tells Wayne that Dylan is not his biological child.
|#16||The Gun Song|
The ladies of Wisteria Lane meet Susan and Mike's new baby, and Susan tries to change the name from Maynard to Conner. Gaby forms a strong bond with their new tenant, Ellie, who happens to be a drug dealer. Lynette is accused of child abuse, since Kayla called and told a doctor.
Several residents of Wisteria Lane are faced with deadly threats when Katherine's ex-husband wants to see his daughter again. Susan realizes she will soon lose her daughter when she goes off to college early, and Katherine Mayfair's secrets are finally revealed. In the closing moments of the season finale, the show flashed ahead five years, which brought many surprising changes in the lives of the Housewives.
Desperate Housewives Season 4 Episode Guide Content licensed under the GNU Free Documentation License.