 When Merlin the Magic Mouse and Second Banana travel to Ireland via magic carpet and crash-land in a shamrock patch, they come across a crazy old leprechaun named O  Reilly. When the mystical creature doesn t believe Merlin can do magic tricks, the magician rodent performs for him. Then thanks to his OWN magic, O  Reilly steals Merlin s pocket watch, resulting in a crazy chase to get the watch back, ending with a collision course on Big Ben!