Manna from Hades

Eleanor Trewynn, recently widowed, returns home from years of working overseas to retire to the cozy village of Port Maybn in Cornwall, England. Even in retirement though, she continues her charity work, leasing out the first floor of her house to a charity shop.
One morning as she opens the shop, she finds both a particularly valuable donation and a corpse stuffed into the storeroom. The donation is linked to a violent robbery in London but the corpse looks nothing like the robbers being sought by the police. With the help of her niece, Detective Sergeant Megan Pencarrow, and, begrudgingly, Detective Inspector Scumble, Eleanor is determined to unscramble this confounding case of daring theft, double cross, and murder most foul.