This three-part work provides material for the party of a detective story club. The first “clue” for the party is a postcard series with letters on the reverse side of the postcards. They can be arranged like an alphabet puzzle and are then turned over to decipher the invitation text. The second part of the work is a large-scale poster for outdoor use, the numerical code of which can also be deciphered as an event announcement. The person who, at the party venue, finally discovers the small hidden print on an indoor sign, which is the third part of the work, will receive a gift.