Inspector Arnold and Desmond Merrion have tackled many curious and difficult cases in their time but never one which led them on a longer and more puzzling trail than the death of Donald Carswell. It began when a sudden summer flood swept down on Brensford and marooned visitors and inhabitants alike in the attics and top floors of their houses. Before the waters had gone down a killer had struck. It was the odd behavior of many of the suspects which first began to puzzle the man from the Yard and his friend. Each theory they tested seemed to point to a criminal activity—but none of them seemed to point to a murderer. Arnold's steady determination and Merrion's fertile imagination make the two a formidable team. But in ''Death Takes a Detour'' they need to use all their ingenuity and resources to untangle an absorbing and complex case of the sort for which Miles Burton is famous.