On Wednesday, CBS will premiere an all-new episode of "Criminal Minds" in which the FBI's Behavioral Analysis Unit (BAU) will make their way to West Virginia to investigate a murder involving a family feud and the legendary tale of the Mountain Man.

The upcoming episode, "Blood Relations," will center on an intense rivalry between the Howard family and the Lee family that eventually leads to murder. A promo for Episode 20 also reveals that the storyline will center on the horrifying tale of the Mountain Man, a killer who was born 40 years ago and is part of the Appalachian population.

According to TV Guide, the official synopsis reads: "When two murder victims are found in a backwoods community in West Virginia, the BAU will uncover a long-simmering feud between two families and must investigate which side could be responsible for the deaths."

CarterMatt reports that fans can expect the Matthew Gray Gubler-directed episode to depict elements similar to "Hatfields & McCoys," except for that it takes place in modern times and the actions of a few are more sinister.

A number of actors will make a guest appearance in Episode 20, including Adrienne Barbeau as Cissy Howard, Tobin Bell playing Malachi Lee and Ronnie Gene Blevins as Miles Lee, reports Hollywood Hills.

Later on in the season, "The Office" alum Brian Baumgartner will guest star on the CBS sitcom as a serial killer. TVLine reports that Baumgartner will play a man who ends up at an unexpected crossroads in his life and then goes on a killing spree in the season's 22nd episode, "Fatal."

"Criminal Minds" S9E20, "Blood Relations," will air on Wednesday, April 2 at 9 p.m. EST on CBS.

Watch the promo video below.