Boss and Rosco find leprechauns in the Irish countryside and steal all their gold. When the leprechauns turn the tables, the Dukes have to save Boss before they send him over the rainbow.

Boss babysits his niece, Cindy Sue, while he races the Dukes through Austria. He calls a truce so the Dukes can babysit while he buys the stolen Crown Jewels of Austria. But, the crooks kidnap the Dukes and Cindy Sue and ransom her to Boss for $1 million.

Boss has a crook named Geraldo run the Dukes off the road. They are helped out by a boy named Pepino and his racehorse, El Blanco. Pepino is racing the next day to save his grandfather's ranch. Geraldo wants his horse, El Diablo, to win so he has Boss steal El Blanco. The Dukes have to find the horse, win at the track and get back in the race.

Since there's no racing on Christmas, the Dukes and Boss stop to celebrate the holiday. However, Boss plans to break the rules and seek back to racing on Christmas Day. Because of his similarity to Ebenezer Scrooge, Boss is forced to live his own version of ""A Christmas Carol.""

Boss meets with poachers, the Bouchard brothers, to buy some illegal furs. When the poachers catch Suzzette, a local girl who loves animals, snooping around it's up to the Dukes to help her out.

Jesse finds Cyrus Duke's treasure map and meets up with Bo, Luke and Daisy in the Phillippines to find it. They are going to turn in the $20 million so they can get the reward and pay off the mortgage. Unfortunately, the Dukes are going to have to outmaneuver Boss and a crook named Richards, who are after the treasure for themselves.