Crime & Mystery: Bakerstreet Files begins with choosing one of the four different criminal cases. A short outline of the case is read out and then every player draws a suspect he has to probe and takes a number of evidence cards. Evidence cards can describe any point of time before, during or after the deed. Each card provides evidence for all the suspects; this means, players have to pick those pieces of evidence which correspond to his or her suspect (as indicated by identical letters on the evidence and suspect cards). Next, the first player gives his or her 'report of investigation' by devising a story which draws on every piece of evidence provided by the evidence cards. Ideally, the players' reports - though presented in a matter of fact style - not only merge all the pieces of evidence but also entertain all the takers. For example, the evidence 'looking at a family portrait for a long while' could be translated into the following narrative: 'Mr. Harker finally prepared to walk out of the room, but before leaving, he suddenly looked back and stared at the wall behind me. I also turned around and spotted the ancient family portrait painted in black and white.' Players report one after the other and as a general rule the more detailed a report, the greater the difficulty for the other players to assign all the pieces of evidence to the suspects.

After every player has given his or her report, all evidence cards are shuffled again and seven of these cards are randomly drawn. The correct evidence which is written on the back of each card is not visible to the naked eye but must be deciphered with the help of the red foil. Using the foil, the seven clues are read out aloud by one of the players. Now the other takers have to remember the details given in the reports and decide which piece of evidence corresponds to any one of the suspects. Players write down their conclusions on their suspect sheets. Finally, each player notes the name of the suspect he or she things of as being the culprit. In general, this will be the suspect to whom most of the evidence points, but players may also choose a different suspect in case they do not trust the presentations and wish trust in their gut feeling.

During the scoring phase, players get two victory points for each piece of evidence which was correctly assigned to the corresponding suspect. There is one exception: the player who interrogated the suspect himself only scores in case at least one other player has assigned the evidence to his suspect. This restrains the players from giving reports unrelated to their evidence.

Crime and Mystery: the Bakerstreet Files is a small conversational game. It is best played with four or more players, who have a partiality for relating. The game heavily relies on the players' ability to give lively and interesting reports. If players simply rattle off one piece of evidence after the other there is no chance of conjuring up the adequate atmosphere and the game can be boring under these circumstances. However, in case players present exiting reports, the Bakerstreet Files can be a very interesting diversion after a hard day. It is definitely a party game and should be played quickly and airily. It will hardly last longer than 30 minutes and, personally, I felt extremely tempted to retry the game more than once. But watch out: More often than not the players' recollection will be confused by the reports given during the previous game(s) and not later than the third round everyone will be completely ditsy and the game will degenerate into nothing more than guesswork.