Minerva, owner-operator-proprietress of a Mineral Spa that caters to millionaires, uses her dastardly Deepest Secret Extractor to pick the brains of her wealthy customers and to locate their hidden valuables. While Bruce Wayne and another wealthy patron discuss the collection of priceless diamonds in the safe at The Wayne Foundation, Minerva eavesdrops and cleverly swipes Bruce's wristwatch from the locked box in which he place his other valuables. Later, she contacts Bruce by phone and tells him they found his missing timepiece and he will receive an free-of-charge Eggplant Jelly Vitamin Scalp Massage if he comes to collect it. Arriving at Minerva' spa, Bruce receives the full scalp treatment, including Minerva's Deepest Secret Extractor, with which Min uncovers the combination to the Wayne Foundation vault! While Bruce leaves Minerva receives a call from Lord Easystreet, asking her for an appointment. Bruce rushes around the corner to the alley where Robin is waiting in The Batmobile; there he becomes The Caped Crusader and he and The Boy Wonder return to the sinister spa. Suspecting The Batman is on to her scheme, Minerva orders her men Adonis and Atlas to put The Dynamic Duo into her Persimmon Pressurizers to parboil them. While Batman and Robin are left to cook, Minerva enters The Wayne Foundation Vault and swipes the diamonds from within; after which, she rescrambles the combination and hands them over to French Freddy, The Fence. She returns to discover to her shock that Batman and Robin have escaped, with the aid of their Steam-Neutralizing Batpellets...but she decides to rob Lord Easystreet before skipping town. Later, The Caped Crusader and the Boy Wonder question Minerva at Police HQ, where, of course, she denies the whole thing regarding their attempted murder or any of the robberies. Suspecting that she lied, The Batman sets a trap for her, and Barbara Gordon agrees to assist by making sure the true Lord Easystreet fails to keep his appointment at the spa by detaining him at the library; she notifies him about a certain book he is searching for which has finally turned up there. While The Lord goes to The Gotham Library, Alfred, who is Easystreet's doppleganger, replaces him and keeps his appointment at Minerva' Spa; here, Min prepares to put Alf under her Deepest Secret Extractor. Meanwhile, The Caped Crusader learn that the combination to The Wayne Foundation has been tampered with, and uses his Three-Second-Flat Batvault Combination Unscrambler to break inside and uncovers the diamonds' theft. He then realizes Alfred is in danger, and, along with The Boy Wonder, he heads back to the spa. Minerva soon learns that Alfred is a phony and tries to discover his real identity; before she can do so, The Caped Crusadress, Batgirl, shows up---only to be immediately nabbed by Adonis and Atlas and placed, along with Alfred, into the same Persimmon Pressurizers which failed to do in The Dynamic Duo earlier. Minerva discovers that Fredy The Fence has blown town with The Wayne Diamonds and prepares to follow him, but is blocked by Batman and Robin. She releases Alfred and Batgirl and sics Adonis and Atlas on The Dynamic Trio; during The Batfight, she tries to escape, but fall into the waiting hands of Commissioner Gordon and Chief O'Hara, who arrive with Freddy (who was nabbed at Gotham Airport) and to take Minerva and the now-subdued Adonis and Atlas into custody.
At the end Alfred and Batgirl joke about the their mutal secret-the secret of Batgirl real identity as barbara Gordon which was introduced in Enter Batgirl, Exit Penguin as that epsiode was the first introduction of Batgirl intot he series-this episode was the last apperance of Batgirl in the series.
As the 1966 Movie Batman was supposed to be an introsuction of Batman and Robin, Batgirl doesnt appear in this movie
A cameo apperence is made by the series producers William Dozier and Howie Horrowitz.