Kathy Kane, still bound by her promise to Batman not to assume her Batwoman identity to fight crime, does it nonetheless to go to a costume party. At the same time, Batman and Robin are carrying out an attack on the mob of a mysterious, masked gang boss who is attempting to loot the mail car of a passing train. Batman twists his ankle and is rendered helpless. The masked gangster, whose mask covers the same area of his face as Batman's tries to escape on the train but is choked by its smoke and falls off, hitting the ground so hard he gets amnesia. As fate would have it, Batwoman is passing by on her cycle and sees Robin chasing the gang-boss, who has instinctively discarded his mask. When she catches up to them, she recognizes Briggs as a former athlete and gym owner, and deduces incorrec