The secluded beauty of Ceredigion provides a backdrop to the intrigue of detective drama Hinterland, also known as Y Gwyll. From the coastal marshes of Aberystwyth to the wild forests and ex-silverlead mining hamlets in the Cambrian Mountains, the locations of the show offer a sense of mystery and atmosphere that has helped to make it a hit in over 100 countries.

The dark tones and brooding characters of the series are influenced by popular Scandinavian crime dramas such as Wallander and The Killing, and the programme is filmed in both English and Welsh. This combination is proving successful, as Hinterland has made it onto the BBC schedules in both countries.

It’s a rainy morning in Llanybydder, Carmarthenshire, and the fog is thick around the old school where Hinterland is filming its third, and possibly final, series. Inside, extras huddle in the canteen, reading books and doing crosswords in complete silence for fear of disturbing the filming. Make-up bags hang on the walls of the former boarding school, which has been left derelict after its most recent residents – an Islamic college – moved out in 2012.

It’s here that DCI Tom Mathias investigates a mysterious disappearance. His first clue comes from a bungalow where he finds the bathroom covered in blood. Then he ventures up into the mountains, and discovers that Helen Jenkins has been thrown from the parapet of Devil’s Bridge. It’s a location that is a favourite of the programme’s creators, Ed Thomas and Ed Talfan, who say that they were inspired by their visit to the mid Wales spot in 2013. In fact, they visited it twice, as they wanted to get just the right shot.