After leaving the tropical paradise of Saint Marie in search of a quieter life, Humphrey Goodman takes up the position of DI in the sleepy Devon town of Shipton Abbott, the home of his fiancée Martha. However, their dream of living happily ever after together is quickly shattered when a crime wave unexpectedly hits the town. With his formidable investigative experience, Humphrey sets out to crack a range of criminal cases in the hope of restoring the peace and tranquility of this corner of rural Britain.