You remember Mr. Mack, the man who was so memorably saved from a pile of poo in The New York Times bestseller The Giggler Treatment. He's now become an inventor, which quickly lands him in jail. Mrs. Billie Jean Fleetwood-Mack is missing and Robbie and Jimmy Mack attempt a prison break. Meanwhile, the slugs of Dublin have launched a bid for world domination. Can the hilarious Mack family rush to the rescue just one last time?