The Rivals of Sherlock Holmes S01 E01 A Message from the Deep Sea

This episode features Dr Thorndyke, played by John Neville, who is first a medical man and second a solver of mysteries. A young girl has been murdered in her boarding house and the solution looks obvious - but is it? Neville plays the sleuth with aplomb and this is a strong opening episode. The character is arrogant, capable, and likable - and of course his intelligence makes his police colleagues and/or adversaries look like idiots!