By ROBIN MIZRAHI and MICHAEL GLYNN

Clean up on aisle 7! A simple trip to the grocery turns into a bloody rampage as former "Roseanne" star Laurie Metcalf joins the cast of "Desperate Housewives" and goes berserk on the women of Wisteria Lane.

That's just one of the bombshell developments that the "Desperate Housewives" writers and producers have in store for the wacky Sunday night soap during November sweeps.

After last season's string of hit-or-miss episodes the cast and writers at "DH" are finally "on their game again," a show insider tells The ENQUIRER.

"The carnage at the supermarket represents what viewers love best about the show — shock and humor at the same time," said the insider.

A violent chain of events is set off when Lynette (Felicity Huffman), Nora (Kiersten Warren) and Edie (Nicollette Sheridan) go to the grocery store and run into new neighbor Carolyn Bigsby, played by Metcalf.

Lynette puts her foot in her mouth by introducing Nora to Carolyn as "The woman my husband had an affair with before we were married."

The misguided joke sets off Carolyn — because she's actually on the premises to kill her cheating husband, who owns the store. She pulls a gun and takes the three women hostage!

Then, just as the SWAT team arrives, Carolyn panics and begins firing the gun wildly. After wounding Lynette in the arm and killing Nora, she points the gun at Edie. But before she can fire, Carolyn is taken out in a hail of bullets by the SWAT team. When the smoke clears, a grief-stricken Lynette convinces Tom (Doug Savant), to add another child to their brood — by adopting the daughter he'd had with Nora during their affair.

"The new story lines should have viewers desperate for more," said the insider. And they'll get it! In the Solis household, Eva Longoria and Ricardo Chavira, in the roles of husband and wife Gabrielle and Carlos, will play out a "War of the Roses" scenario — living in the same house while despising each other.

"Gabrielle will try to become financially independent by resuming her modeling career, but at 30 years old, she finds herself competing against a 14-year-old anorexic," said the show insider. "And to her horror, she's hired as the girl's dumpy mother!"

Producers are also planning on hiding Marcia Cross' pregnancy — she's due to have twins in April — by dressing her character (Bree) in loose fitting clothes and getting her to stand behind a number of different props.

Additionally, Dixie Carter will join the cast as Bree's monster mother-in-law.

"'Housewives' is back in the groove and locked into the magic of its first season," said the insider.