First look images released from second series of S4C smash hit mystery drama, Y Golau

The series, titled Y Golau: Dŵr, will air in Welsh, with subtitles, on S4C from 14 September 2025The English-language version, The Light in the Hall: Still Waters has been acquired by Channel 4 and AMC+.

Y Golau: Dŵr returns to Llanemlyn, where a controversial redevelopment plan to expand the reservoir is reigniting old tensions. The story captivates Caryl, a young journalist, who becomes entangled in a complex web of personal betrayal, familial secrets, and dark mysteries, which raises doubts about the imprisonment of Rhys Owen for the murder of his cousin Llŷr during the protest against the expansion in 1995.

Season one of Y Golau premiered on S4C in May 2022 with an English language version televised on Channel 4, and was a ratings hit.

The second series returns to the fictional village of Llanemlyn and features an all-star ensemble cast with Siân Reese-Williams (Hidden/Craith, 35 Diwrnod, Hinterland/Y Gwyll) as Caryl Huws, Mark Lewis-Jones (Yr Ymadawiad, Y Sŵn, Dal y Mellt) as Rhys Owen, Nia Roberts (Tree on a Hill/Pren ar y Bryn, Yr Amgueddfa, Hidden/Craith) as Eve Davies and Robert Glenister (Sherwood, The Night Caller, Hustle) as Robert Davies.

The supporting cast include Tom Rhys Harries (who will play the title character in the DC Universe film Clayface, which starts filming this Autumn) as Hari Breckon, Maeve Courtier-Lilley as Mabli Davies Owen, Wyn Bowen Harries as Bryn Owen, Mali Tudno Jones as Megan Breckon, Matthew Gravelle as Gareth Breckon and Gillian Elisa as Eunice.

The series is created by Regina Moriarty (creator and lead writer of the first series of Y Golau/ The Light in the Hall) who has also written two of the episodes. The other four episodes have been penned by other leading Welsh writers; Siân Naiomi (The Indian Doctor, and co-writer of the first series of The Light in the Hall), Anwen Huws (Keeping Faith, Gwaith/Cartref, and co-writer of the first series of The Light in the Hall), Catherine Linstrum (Nuclear, Primeval) and Angharad Elen (The Crown, Stad, Deian a Loli).

Y Golau: Dŵr is a Triongl, Long Story TV and APC production for S4C, made in collaboration with AMC+, Channel 4 and the Welsh Government via Creative Wales.

Y Golau: Dŵr was commissioned for S4C by Gwenllian Gravelle, S4C’s Head of Film and Drama, and the English-language version The Light in the Hall: Still Waters was co-commissioned by Channel 4. Both are Triongl / Long Story TV productions for S4C.

Producer Nora Ostler Spiteri said: “It has been a pleasure to collaborate once again with Long Story and APC to bring this story to the world. A big thank you to Gwenllian Gravelle and S4C for their warm support and to Sundance Now, Creative Wales, and C4 for making this possible.

“It has been wonderful to collaborate with such a talented cast and crew, and it was lovely to return to Llandovery to bring the world to life.”

Gwenllian Gravelle, S4C’s Head of Film and Drama said: “After the runaway success of Y Golau Series 1, the world of Llanemlyn returns with a mystery darker, deeper, and more thrilling than ever with Y Golau: Dŵr.

“With a powerhouse cast and a story that grips from the first moment, this is one journey our S4C viewers won’t want to miss.”