Sherlock Holmes is hired by the Earl of Morcar to escort him on his train journey between London and Liverpool. But the implacable logic of the detective will soon be put to the test: stolen diamonds, a mysterious death, and kidnapping of a princess. Fortunately, he is accompanied by his faithful sidekick, Dr. Watson. But his enemy of always, Moriarty, is also of the voyage...

Sherlock Holmes is a comic combined with a game, one title in a series subtitled "The comic in which you are the hero". You embody a character in an immersive story in which your choices guide your progress. You have a character sheet akin to those used in role-playing games that tracks your possessions, your special abilities, your coins, and your victory points. In general, gameplay consists in following the comic's panels — which contain clues, riddles and traps — and making choices about where to go and what to do, while using your visual perception to collect clues and be smart enough to resolve the riddles. As in any game, you can lose — sometimes really badly!