Sherlock is frustrated because he thinks there’s a mastermind behind the Noahtic and Drebber cases whose identity eludes him. Returning on a train after an unsatisfying investigation into another aristocrat’s death, he happens to meet William again.

With 48 minutes remaining before the train reaches the next station, Sherlock declares that William and he can find the murderer in time. Sherlock relies on the evidence at the scene, while William pursues a psychological profile of the killer.