"The Trick Diamond" is the key to unlocking a treasure hidden within Gaudí 's famous Park Gruell. The crime lord Mark Williams was in possession of the diamond but has recently passed away. However, his will gives Lupin a chance to gain the object of many a criminal's desire. Lupin is in for quite a shock though as Mark's conditions are quite unique. Mark replaced six treasures with copies and has kept the originals for himself. Now, Lupin must prove his talent by switching the originals back into place within seven days. Only then will he be given the location of the diamond. (thetvdb.com)