Death Valley is a 2025 crime mystery television series starring Timothy Spall and Gwyneth Keyworth, which premiered on 25 May 2025 on BBC One. In August 2025, it was renewed for a second series, set to air in 2026.
Set in South Wales, the six-episode murder mystery series follows the unlikely crime-solving partnership between eccentric national treasure John Chapel (Timothy Spall), a retired actor and star of hit long-running detective television show Caesar, and socially obtuse Detective Sergeant Janie Mallowan (Gwyneth Keyworth).
The six-part series is written and created by Paul Doolan. Timothy Spall and Gwyneth Keyworth were cast in the lead roles in May 2024. Also in the cast are Steffan Rhodri, Alexandria Riley and Melanie Walters. Guest stars include Kiell Smith-Bynoe, Sian Gibson, Patricia Hodge and Jim Howick.
According to Doolan, detective Janie Mallowan takes her name from Agatha Christie's married name, Mallowan, and from Christie's character Jane Marple.
Filming took place in June 2024 in Penarth, particularly Penarth Conservative Club and Penarth Pier, and in Llantwit Major in the Vale of Glamorgan, including St Illtyd's Church there. Filming on the second series took place in Penarth in 2025.
The series premiered on 25 May 2025 on BBC One and BBC iPlayer.
The Guardian declared it a quality cosy mystery series, calling it "witty and fun". In The Daily Telegraph Benji Wilson gave the opener four stars out of five; "Timothy SpallâÂÂs witty sleuth proves a rival for Ludwig".