Paris, 1927. It's springtime in Paris and Joe Sandilands, a Scotland Yard detective, has flown in to attend an Interpol conference. However, he is promptly diverted to the Quai des Orfevres where his old friend, Sir George Jardine, has been arrested for murder. George is confined to a cell at police headquarters, his evening dress stained with the blood of the man he is alleged to have knifed to death at the Folies Bergere. Beaten by his interrogators, George is in a sorry state. Why, then, is he so reluctant to confide in Joe? The deteceive's enquiries reveal a dark current of vice and murder lurking underneath the gaiety, champagne and dancing - and Joe comes within a whisker of death before finding the killer.