This article is about Marsha, the Queen of Diamonds who has no relation with the Royal Flush Gang.
At Chief Miles O'Hara’s orders, police officers are stationed outside "U. Magnum Diamonds", in lookout for Marsha, Queen of Diamonds’ possible attack. A motorcade approaches the officers where Chief O’Hara steps out of the silver Rolls Royce with Marsha, stunning the officers. O’Hara and Marsha enter the jewelry store, taking the Pretzel Diamond from the jewelers inside the store, while O’Hara continues to profess his undying love with Marsha. Meanwhile, Batman and Robin, along with Alfred Pennyworth, are testing a gigantic "Bat-Diamond" in the Batcave when they get the call from Commissioner Gordon about the burglary as well as O’Hara’s alleged involvement. It turns out that Marsha, Queen of Diamonds, has Miles in a birdcage, and under her magic spell, along with at least three other victims. In order to get her victims, Marsha uses Cupid, a foot tall statue that throws darts equipped with a love potion, each dart is activated with a remote controlled device. Marsha now tries to find out the whereabouts of the "Bat-Diamond", and is eager to break into the Batcave and find out Batman's true identity, where the diamond is stored. Commissioner Gordon does not wait for Batman and Robin to arrive at Police HQ, instead he visits Marsha, asking about the whereabouts of O’Hara. Marsha activates the love dart, sending Commissioner Gordon under her spell and in captivity. Marsha visits her basement where Aunt Hilda, a witch specializing in new potions, resides; she asks Hilda about a special potion for Batman, knowing he is more resistant to ordinary potions. Batman and Robin visit Marsha, where she activates the potion dart on Batman. Using “every ounce of willpower”, Batman resists the potion and escapes Marsha's clutches. An infuriated Marsha sends her men to do battle with Batman and Robin, during the fight Marsha plants another dart on Robin. Marsha extorts Batman by holding Robin hostage in exchange for the Bat-Diamond, including a visit to the Batcave. Batman refuses Martha’s demands, where he vows not to allow anyone else in the Batcave. But Marsha, wanting to bilk him out of all his money, gives Batman an ultimatum by giving another “vow”, she proposes marriage to Batman; thus allowing her to enter the Batcave and reveal his secret identity. Should Batman refuse the marriage offer, Robin, Commissioner Gordon and Chief O’Hara would all be under her captivity, forever. Thus, in order to save them, Batman has no choice to marry Marsha. As the marriage is being televised on Gotham City TV, Alfred and Aunt Harriet ponder what to do about the impending marriage. The final scene shows the wedding ceremony between Marsha and Batman, where Marsha says “I do” but Batman is holding out whether he will say “I do” (and have the location of the Batcave and his true identity revealed), or say “I object”, and lose his only adoptive son, Robin for the rest of his life.