"“Who is he?” I asked. “The worst man in London,” Holmes answered, as he sat down and stretched his legs before the fire." And so begins this Sherlock Holmes adventure with the most morally corrupt and vile man in London. A man whom Sherlock must accept into his home and treat with professional courtesy despite intense personal disgust and animosity. What power does this man hold over Holmes and the other people he forces into terrible situations? - Summary by phil c