British mystery series produced by Thames Television which dramatized stories by contemporaries of Arthur Conan Doyle such as Baroness Orczy and Jacques Futrelle. The detectives created by these authors and others were considered the rivals of Sherlock Holmes in their day, thus the title of the series.
A gypsy sets out to prove that a police detective is wrong about who killed a woman. Who murdered Mrs. Arryford? The answer is obvious to detective sergeant Grubber - but not to Hagar the gypsy. It takes all of her gypsy intuition to arrive at the solution.