Perry Mattfeld, Brooke Markham, and Keston John have joined the CW pilot “In the Dark” in lead roles, Variety has learned.

The project follows a flawed and irreverent blind woman named Murphy (Mattfeld) who is the only “witness” to the murder of her drug-dealing friend. After the police dismiss her story when no body can be found, she sets out with her dog, Pretzel, to find the killer while also managing her colorful dating life and the job she hates at Barking Blind- the guide dog school owned by her overprotective parents.

Markham will play Jess, Murphy’s roommate and best friend. She is described as a well-meaning, nurturing veterinarian who is somewhat overly protective of Murphy, much to Murphy’s occasional irritation.

John will play Darnell, a local drug dealer whose young cousin, Tyson, was dealing for him. He initially dismisses Murphy’s claims that she found Tyson dead in an alley before his body mysteriously disappeared. But as she pursues her investigation, he begins to realize that Tyson may really be dead.

Mattfeld most recently appeared in Showtime’s hit series “Shameless” as Mel. Markham previously starred in the YouTube Red series “Foursome.” John has appeared in shows like “Bosch,” “24,” and “Vinyl.”

Mattfeld is repped by Innovative Artists. Markham is repped by Paul Kohner Agency and Gotham Group. John is repped by Buchwald and Sinclair Management.

Corinne Kingsbury will write and executive produce “In the Dark.” Ben Stiller, Jackie Cohn, and Nicky Weinstock will also executive produce via Stiller’s Red Hour Films. CBS Television Studios will produce in association with Red Hour Films. The series was inspired by The CW’s work with Guide Dogs of America through their charitable arm, CW Good.