Sherlock Holmes and Dr. Watson bump into one another in an infamous opium den in East London. Holmes is on a commission from a lady in Kent to find her husband, who has gone missing. For no apparent reason, they travel to her family house in Kent and spend a bizarre night of bumpiness, but by dawn Holmes has made a startling deduction. They travel back to London, to Bow Street police station, where they reveal the culprit and a solution to the mystery. When they go in search of breakfast afterwards, they encounter Professor Moriarty, who always starts his working day even earlier than the famous detective duo.