This is an engrossing episode from "The Return of Sherlock Holmes" series--THE DEVIL'S FOOT. It starts out as possibly being a tale of the supernatural but instead the vacationing Sherlock Holmes uses reason to figure out who did the murders and why.
Brett and Hardwicke are well cast as the sleuth and his doctor friend, vacationing on the Cornish coast after the famous detective has suffered a nervous breakdown. They should have known better than to go this lonely locale expecting to find peace and solitude in the great outdoors far away from Baker Street.
Of course, it doesn't take long before a man turns up at their door with a story about three brothers and a sister enjoying a quiet game of cards, with one brother leaving after a brief quarrel. In the morning, the sister is found dead of apoplexy and the brothers are in a state of acute dementia with their faces frozen in horror. Holmes has to find out what caused the tragic occurrence--and why.
I found it one of the more interesting, if less baffling of the Holmes stories, but effectively produced with the proper atmosphere and settings. The explanations seemed credible and satisfying enough for any mystery fan. Well worth watching.