GRIMM Signs WEEDS Alum Kate del Castillo for Halloween Episode Guest Role

From Buffy The Vampire Slayer and Angel executive producers David Greenwalt and Jim Kouf comes a new world of police work where all cases have a storybook connection... but not always ending happily ever after. The second season of Grimm premieres on NBC August 13th, 2012.

Remember the fairy tales your parents used to tell you before bedtime? Well, those weren't stories, they were warnings. Detective Nick Burkhardt (David Giuntoli) thought he was ready for the grim reality of working homicide in Portland, Oregon. That is, until he started to see things... things he couldn't quite explain. Like a gorgeous woman suddenly transforming into a hideous hag, or an average Joe turning into a vicious troll. Then, after a panicked visit from his only living relative, Nick discovers the truth about his visions: he's not like everyone else, he's a descendant of an elite group of hunters known as "Grimms" who are charged with stopping the proliferation of supernatural creatures in the world.

And so begins his new life journey - albeit a reluctant one at first - as he solves crimes with his partner who knows something about Nick has radically changed but can't quite put his finger on it. Along the way, Nick finds himself unexpectedly getting help on some of the more difficult cases from Monroe (Silas Weir Mitchell), a guy who seems normal at first but is soon revealed to be what you might call a "big bad wolf." Literally! While the Brothers Grimm wrote fairy tales that children have adored for generations, imagine if the villains were real, and Nick was the only one who could stop them.

Kate del Castillo (Weeds) has signed on to play Detective Valentina Marquez, who travels to Portland from Albuquerque in pursuit of a serial child abductor she has spent the past five years tracking, in Grimm's Halloween episode titled 'La Llorona'.

According to The Hollywood Reporter, the episode will follow the Mexican legend of The Weeping Woman (La Llorona), a woman who drowns her children in order to be with the man she loves. After he rejects her, she commits suicide but is not permitted to enter the afterlife until she finds her drowned offspring. She is forced to wander the Earth, crying, until she finds the missing children.

Grimm, from executive producers David Greenwalt (Angel, Buffy the Vampire Slayer) and Jim Kouf (Angel, National Treasure), stars David Giuntoli, Silas Weir Mitchell, Russell Hornsby, Sasha Roiz, Bitsie Tulloch and Reggie Lee. The second season is set to premiere on NBC on Monday, August 13th, at 10/9C before moving to it's regular airing date on Fridays at 9/8C.