Sherlock Holmes and Watson are back! Someone or something is killing men in London, leaving behind bodies drained of blood and bite marks upon their necks.

Faced with the possibility that London is under a vampire attack, Sherlock Holmes is asked by Scotland Yard to help uncover the true killer or killers. It doesn't take long for Sherlock to sniff out a trail that leads to a bar along St. Katherine Docks. Shortly after that, the bar's owner goes missing.

The game is very much afoot.

Sherlock Holmes and Dr. Watson join the hunt for the man... and in the process come across an improbable ring of immortal spies, of which the duo are soon recruited into. It is a cat and mouse game, with Sherlock and Watson as the bait. But with London's most famous detective on the case, it's not a matter of if the killer will be caught... but when.