Mr. Jack: Extension is an expansion for the Mr. Jack deduction game that features refreshed artwork for the tenth anniversary of the game as well as an original character as strong as it is enigmatic: Professor Moriarty, whose special ability is to imitate one of the characters who is not at stake. Moriarty is quite the chameleon, impersonating the other detectives by mimicking their appearance and using their abilities!

This expansion lets you play with six new characters: meet the sultry Madame, flee the terrifying Pizer, avoid the revolutionary Joseph Lane's barricade, dodge Inspector Abberline's probing questions, bound along London's streets with the Spring-Heeled Man, and watch out for Moriarty. At the start of the game, choose which of the eight characters to play with via a draft and determine their starting locations. These new possibilities add fun and strategic depth.