This game is for anyone aged 7 to 97, alone, with family or in a group. A course is suitable for people with reduced mobility. With the help of some essential information on the back of this document and the location plan of the survey sites, the participant must join and go through several sites of the Ivryen heritage in order to find the figures that will allow him to find the solution to the following puzzle: In the tenth century Raoul d'Ivry asked his wife Alberède to find an architect to build the castle that his half-brother Richard 1st Duke of Normandy asked him to build to defend the duchy’s border. Alberède entrusted the construction of the fortress to Lanfred, who produced a work described by historians at the time as «strong and impregnable». So Alberède, who does not want to see any similar achievement, imprisons Lanfred. There is a possibility of making Lanfred escape by solving, from clues, the enigma that will open the door of his prison....