The story opens in a Western saloon, where a young musician with a banjo begins to tell a tale of Lucky Luke and his sworn enemies the Dalton brothers: Joe, William, Jack and Averell. Luke has, once again, as he has done many times before, thrown the four outlaws into jail. The prison is also the abode of a guard dog named Rin Tin Can (Rantanplan in the original French language version). No sooner have the Daltons entered the jail than they are met by a lawyer named Augustus Betting. Betting informs the brothers that their Uncle Henry Dalton has died by hanging. However, over the course of his criminal career, Henry Dalton amassed quite a fortune, and has chosen to leave it all to his nephews on the condition that they kill the judge and jury who sentenced him to death. To make sure that the task is completed, Henry Dalton states in his will that his nephews must be accompanied by the only honest man that he has ever known, Lucky Luke. If the task is not successfully completed, the entire fortune will instead be given to charity. The brothers then decide to tunnel out of the jail, but end up digging into the dynamite storage building. When Averell lights a match, the building blows

埃及女王克利奥帕特拉和凯撒大帝打赌，将在3个月内建造一座宏伟的宫殿。克利奥帕特拉把这项任务交给了建筑师爱狄费斯，并下令如果在规定时间内没能完成任务，他将被投进鳄鱼池。 在这么短的时间内建造一座宫殿根本就是不可能完成的任务，但有一个人可以帮助爱狄费斯，那就是魔法师凯塔福克斯。于是爱狄费斯来到高卢的村庄，请求魔法师的帮助。凯塔福克斯欣然前往，同他一起来的还有