Sherlock on Masterpiece

PBS | 9:00 pm

"The Final Problem" is the title of the last of the mysteries that comprised the drama’s relatively brief Season 4. It’s also the name of an actual Sir Arthur Conan Doyle story, but some of its elements were used earlier in this series — and it could mean the end of Holmes and Dr. Watson (Benedict Cumberbatch, Martin Freeman), at least as far as this incarnation of their adventures is concerned.