Written and created by Ed Thomas (Hinterland/Y Gwyll, House of America), the six part series has begun filming on location in Ystradgynlais on the River Tawe, where Ed Thomas grew up.

Laced with humour and a touch of the absurd, Margaret and Clive Lewis are at the heart of it all. Set in a bypassed town at the edge of a valley, this is a story about crumbling values, resilience and transgression being the key to liberation.

With a stellar Welsh cast, the series stars Rhodri Meilir (In My Skin, Hidden) as Clive Lewis and Nia Roberts (Craith/Hidden, Yr Amgueddfa) as Margaret.

”I’m thrilled to have this opportunity to tell this big little story about change set and shot in the place I grew up at the edge of the Brecon Beacons in the Swansea Valley. It’s a world where resilience and a healthy sense of the absurd  is the only thing that will get you through when the situation you find yourself in is desperate – but not serious’, says excited Ed Thomas who has written and created the series.

They will be joined by Richard Harrington (Y Gwyll/Hinterland, The Crown, Gangs of London), Hannah Daniel (Un Bore Mercher/Keeping Faith, Y Golau /The Light In The Hall), Richard Lynch (Pobol y Cwm), Suzanne Packer (Casualty, Bang), William Thomas (Craith/Hidden, Torchwood), Rhodri Evan (Craith/Hidden, The Pembrokeshire Murders), Steffan Cennydd (Pembrokshire Murders, Yr Amgueddfa), Jacob Ifan (S.A.S Rogue Heroes, Bang).

Gwenllian Gravelle, S4C’s Head of Scripted said:

“Pren ar y Bryn/Tree on a Hill will bring an abundance of mischief and dark humour to our screens. We are delighted to be in partnership once again with Fiction Factory, BBC Cymru Wales and Creative Wales for this ground-breaking commission.”

Gerwyn Evans, Deputy Director of Creative Wales, added: “It’s fantastic to be supporting this bilingual drama for BBC Cymru Wales and S4C. This drama is one of six Creative Wales is supporting over the coming year that will air on BBC / S4C. We’re delighted that by providing funding and support more and more dramas are being made in Wales, using our facilities, creating opportunities for crew and trainees and showcasing our stunning Welsh locations.”

Pren ar y Bryn/Tree on a Hill will be broadcast on S4C, BBC One and iPlayer.