On a visit to Wisteria Lodge, Scott Eccles gets a strange reception. A mysterious note arrives for his host, Garcia, and the next morning Garcia and his servants have vanished without trace. Eccles consults Holmes, who decides to treat the case as a murder investigation, but it appears that Holmes and Watson are on a wild goose chase.
Holmes investigates a killing which has all the hallmarks of the worst kind of Ruritanian vampire. He is sceptical (to say the least) about the possibility that the undead are up to their mischief just a short train journey from his rooms in Baker Street. If a local resident really found his South American wife sucking blood from their young son, what might it signify?