When the Joker tricks Batman and Robin into being locked up in an armored car so that he and his gang can loot a book fair, the heroes are liberated by a new super-hero the Eagle, who rips off the doors off the vehicle. He expresses his wish to become their third partner, but the Joker manages to make a clean getaway thru a specially-prepared exit. The Eagle leaps away, but Batman and Robin meet him later that night in the Bat-Cave when he unmasks himself and proves to be Alfred, their butler. Alfred explains that he was accidentally struck by a ray bombardment form a criminal scientist's machine in the Bat-Cave, refracted through a space-crystal prism that Superman brought back from outer space. It had the effect of giving him tremendous strength and leaping power, plus invulnerability. A