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!
This is the only Merlin cartoon where he was beaten by his opponent.
This is also the last Merlin cartoon to be produced.