It is 1884, and when a fellow landlady finds her lodger poisoned, Mrs Hudson turns to Sherlock Holmes.
The riddles pile up as aged big game hunter Allan Quaterma.
Upon investigating, the companions discover that the lodger, a civil servant recently returned from India, was living in almost complete seclusion, and that his last act was to scrawl a mysterious message on a scrap of paper.
The police suspect the landlady of murder, but Mrs Hudson insists that her friend is innocent.
It is 1884, and when a fellow landlady finds her lodger poisoned, Mrs Hudson turns to Sherlock Holmes