The Blackbird Of Prey, The Penguin, his assistants, Dustbag and Pushbroom, and his moll Miss Clean visit The U.S. Mint to conduct their own guided tour of the building. Later, The Dynamic Duo are alerted by the bird and his minions at The Mint, and dash to Police HQ, where they immediately spot Penguin right outside and apprehend him. Upon learning the tricky bird stole absolutely nothing from The Mint, they release him...and decide to see what he's up to. Joined by Batgirl, Batman and Robin head for The Mint and discover that Penguin has infected the tender with the dreaded Lygerian Sleeping Sickness (a disease which puts its victim to sleep for years!) and a supply of the contaminated cash has already been shipped to The Gotham National Bank! While Batgirl speeds to the bank by Batgirlcyle as a ruse, Batman and Robin take The Batmobile to Gotham General Hospital to heck on the supply of Vaccine B-6, the only known antidite to the sleeping sickness. Unfortunately, they arrive in time to discover that Penguin has given himself and Dustbag and Pushbroom a dose of the vaccine, then pours it down the drain, releases 3 Lygerian Fruit Flies, and leaves The Caped Crusader and The Boy Wonder to be bitten alive by the infectuous insects! Batman uses his All-Purpose Batswatter to put 2 of the flies out of their misery; then, he spots the 3rd fly on Robin's nose and uses his Battweezers to remove it and take back with them to The Batcave to analyze. Before they do, they head back to Gotham Bank to relay the news with Batgirl. At the bank, they find that $13,000 of the tainted tender have already been distributed to unknowing Gothamites!

Not knowing exactly which bills are infected, The Caped Crusader leaves nothing to chance and immediately puts through a warning broadcast by radio to the public urging them to get rid of the corrupted cash. As the people dump the money into the street Penguin and his gang promptly vaccuums up Gotham's cash-laden boulevards with giant vaccum cleaners. While The Penguin sorts his newfound wealth, millionaire Bruce Wayne contacts all of the worlds financiers, warning them not to take any of the money now circulating in Gotham City. Realizing he cannot do anything with his infectuous ill-gotten gains, The Penguin threatens to release 500 fruitflies in the city unless Bruce instructs the financiers to accept his money. After consulting with amateur weatherman Alfred Pennyworth, who, with an array of Bat Weather Instruments, informs them that the current weather will be cold and clear, Bruce defies his threat. An incenced Penguin quickly makes good on his ultimatum by releasing the flies, and, believing they did their job, he and his gang set out to rob Gotham's jewelry stores! Finding The Dynamic Trio, Gordon, and O'Hara asleep in the street reassures The Fiendish Fowl that his insidious scheme has come to pass. But as Penguin overplays his hand by trying to remove Chief O'Hara's gold watch, they all jump up and knock the villains cold; Penguin is deposited in the nearest garbage can. The Caped Crusader informs The Billious Bird that the flies were too used to tropical heat and were instantly overwhelmed by the cold weather which crushed them to death. Robin adds that Penguin tricked himself by giving himself that double dose of sleeping sickness vaccine; so large one that he'll probably contract Lygerian Sleeping Sickness himself...and The Penguin falls fast asleep! (It then suddenly starts raining, despite Alfred's forecast!)

Meanwhile, Calamity Jan and her mom, Frontier Fanny, pay a visit on that criminal cowpoke, Shame, at The Gotham State Pen...