Lord Hector Darlington is a wealthy art collector who owns one of the finest private galleries in Europe. His latest purchase is Louis de Granville's 'Adoration of the Magi'. After cancelling a regular trip and returning to view it, Darlington realises the piece is missing. A very unwelcoming Darlington family greet Holmes and Watson at the house, whereupon they discover that it is not only the 'Adoration of the Magi' painting his Lordship should be concerned about.