The Riddler attempts to take control of prize fighting in Gotham, kidnapping the current champ, Kid Gulliver, and brainwashing him into throwing his next fight. While Bruce, chairman of The Gotham City Boxing Commission, watches on TV, The Riddler robs receipts from The Gotham Square Garden box office, and leaves behind a blinking metal box, which puts the cashier in a state of shock! Examining the box, Batman finds it contains a Riddle about a long-buried temple in Southwestern Asia. Later, Riddler, dressed in a burnoose, appears on Betsy Boldface's TV show in the guise of Mushy Nebuchadnezzer, SW Asia's supposed boxing champion. Barbara suspects it's Riddler in disguise and switching to Batgirl, follows Betsey to Riddler's hideout at a little-used gymnasium, where Loreli Circe, The Siren, tries to put her under her spell. She is unsuccessful, since her powerful high note (2 octaves above high "C") works on men only! The Riddler then resorts to having Batgirl tied up and thrown into the steam room, but she escapes through an air vent.
Meanwhile, The Batman solves two more Riddles put through by Riddler over the phone--which is plugged into radio station GTZR--and accepts his challenge to a fight that night at The Garden. There at The Garden, Aunt Harriet, having returned from a trip, greets Commissioner Gordon and daughter Barbara in the audience. As the fight begins, The Caped Crusader has the advantage over The Prince of Puzzlers, but this quickly changes when he is pelted with metal filings by The Riddler and is immobilized by a giant electromagnet hidden under the ring, activated by Betsey. While The Batman is pounded to a pulp by Riddler, Barbara, who bore witness in the audience, leaves to become Batgirl; she finds Betsey Boldface underneath the ring and shuts off the magnet, setting Batman free. The Riddler and his gang retreat hastily and dash back to their hideout, where they are immediately captured.