Susan Calman hosts as three amateur sleuths head to the fictional town of Mortcliff to solve a deadly crime. From the comfort of armchairs in the studio, they watch the drama play out as Mortcliff's crack team of detectives - DI Knight, DC Slater and scene of crime officer Simmons - make enquiries with the local residents. But in a show where everyone has a motive, it might prove harder to catch the culprit than you think. The Armchair Detectives are introduced to suspects, uncover vital clues and share their thoughts and theories as the story unfolds, before making their final accusation in a bid to win the golden magnifying glass trophy.