In the late 1970s, a series of apparent “misadventure” deaths on the Derbyshire moors escalated into one of Britain’s strangest unsolved cases. Six victims were found along ancient footpaths, reservoir lay-bys, and abandoned mining tracks – their bodies staged with unsettling precision.

Then the letters began. Signed “The Surveyor”, they arrived at a local newspaper demanding to be printed, containing OS grid references, ciphers, and cryptic references to drowned churches, corpse roads, and folklore. Police chased suspects. Reporters chased a story.

Then, as suddenly as it began, the killing stopped. The files were boxed, shelved, and eventually forgotten.

The Moorland Letters reopens the investigation forty years later, uncovering lost evidence, new testimonies, and an unseen letter suggesting the police missed a crucial point on the map – and possibly one more victim.

Part true-crime documentary, part Cold War archival mystery, the series examines how cases are remembered, mythologised, and quietly erased.