When a cyber attack on the detectives causes a glitch in Simon Binkle's history machine, Amanda and Nick are thrown back to Victorian London where they must confront a huge black shadow monster that's been terrorizing the city. Suspecting that it may have something to do with Professor Moriarty, they gain entry to a high society ball they believe he's targeting.Young, attractive, and vivacious they're the hit of the ball and no one suspects who they really are.But then the hostess is murdered and Amanda is arrested by none other than her great-great grandfather, Inspector Lestrade, who is convinced of her guilt.Now, alone in the 19th century, Nick finds himself powerless to save her unless he can pull off a miracle: find a way to enlist the help of the one man he fears, Sherlock Holmes. But Success is by no means guaranteed: Holmes is asking a price that might just be too high for him to pay.