Killer Deductions

When Sherlock and John are summoned by Mycroft, they don't expect to meet Diaboli, an infamous assassin, who's talent at deducing has allowed her to escape convictions. The consulting detective and assassin team up as a greater threat looms, but can you ever trust someone who's loyalties are to the highest bidder? And she may not only threaten Sherlock's life, but his heart as well.