In a change of pace episode, Mark begins to believe that Leprechauns are burying gold on the estate. Ignoring Mark's outrageous claims, Hardcastle concentrates on preparing the estate for an upcoming magazine contest. After Benny, Mark's mechanic, is assaulted by a group of men for information about a group of little people, Hardcastle admits that there may be some truth to Mark's Leprechaun story. That night, Mark and Hardcastle set a trap for the "Leprechauns". The trap works and Hardcastle captures the men who have been hanging around his estate. As the judge discovers, however, the little people are not Leprechauns but rather circus performers. Confronting the performers about why they are hiding out, Cluracan, the groups leader, explains that they are fleeing from communist agents that want to return them to their home country as well as Marvin, a circus promoter that had promised their services to Circus Maximus. As for the mysterious gold, Cluracan reveals that it is his family's money. The next day, communist agent Ivan and his men come to the estate disguised as employees of Ladies Garden Monthly, the magazine sponsoring the contest Hardcastle has entered. At the same time, Marvin and his men sneak onto the estate. With the circus performer's help, Hardcastle and McCormick manage to stop the agents as well as Marvin and his men. Later, Mark's continued suspicion that Cluracan's group are secretly Leprechauns seems to be confirmed when a rainbow leads to a mysteriously repaired Coyote.

Le jour de la Saint-Patrick, Hardcastle regarde un programme retraçant l'histoire du peuple celtique à la télévision. McCormick parcourt un livre de mythologie irlandaise...