When Dr. John Watson takes lodgings in Baker Street with the quirky consulting detective Sherlock Holmes, they are both quickly drawn into a mysterious case that has left Scotland Yard baffled. A man is found dead in a south London house, his face a mask of horror, but there are no signs of violence. Meanwhile a mysterious word has been written in blood on the wall and through Sherlock Holmes' observations and deductions, they uncover a tragic tale of love and revenge.