Under Salt Marsh has gripped viewers since its Sky debut in January. The hard-hitting crime drama, released on a weekly basis , unfolds in a close-knit Welsh seaside town torn apart by the killing of a young schoolboy, which reopens old scars surrounding another child who vanished years earlier, reports Wales Online . Here's what you need to know about how much of the Wales-shot and Wales-set thriller Under Salt Marsh draws from real-life incidents and how much springs from pure imagination. No,