When Commissioner Gordon is framed for taking bribes from gangland boss Rupert Thorne, his daughter Barbara pleads with Batman to show up at a rally being put on in the commissioner's behalf by Assistant Commissioner Gil Mason. Batman, hot on the trail of the mysterious figure behind the frame-up, declines, preferring to send Robin in his place. Barbara determined that one way or another the Dark Knight will make an appearance, so she rents a Batman costume and, using her gymnastic abilities, impersonates Batman. Her plan backfires, however, when an unexpected drive-by shooting by gangsters reveals her as a girl. The next day the papers are trumpeting the question, "Who is Batgirl?"