When a group of men and women throughout London begin exhibiting strange psychotic behavior, Dr. John Seward, from the Dracula affair, is brought into the case. Faced with a mystery beyond his realm of experiences, he turns to Sherlock Holmes' trusted companion, Dr. Watson, for help. Together these two men of science must uncover the riddle behind a white powder drug with the ability to drive people mad before the entire population is infected. Also includes a special bonus story, "The Electric Shark", starring Her Majesty's Secret Agent, Quincy Harker.