1902. Sherlock Holmes's latest case begins with a severed finger. With no signs of decomposition and an adverse reaction to silver, it is the most perplexing mystery yet - one that relates to their next client - and the moment Sherlock's and Watson's lives are irrevocably changed.

A Transylvanian nobleman called Count Dracula arrives at Baker Street seeking Sherlock's help, for his beloved wife Mina has been kidnapped. But Dracula is a client like no other and Sherlock and Watson must confront - despite the wild, unbelievable notion - the existence of vampires. And before long, Sherlock, Watson and their new vampire allies must work together to banish a powerful enemy growing in the shadows...