Batgirl (1967)

At the Gotham City library, Barbara Gordon helps Bruce Wayne find a book on butterflies so he can prove a point to a friend, a millionaire explorer. As Bruce and his youthful ward, Dick Grayson, are leaving they spot the villainous Killer Moth and three of his henchmen and, suspecting they are up to no good, determine to return as their superhero alter-egos, Batman and Robin. While the Caped Crusaders are donning their costumes, the criminal quartet knock out the millionaire, lock Barbara in an alcove and prepare to spirit their victim away. When the Dynamic Duo attempt to capture the crooks, they are encased in Killer Moth's silk cocoon. Is this the end of our Gotham City heroes? And why does a beautiful librarian have a cowl and a cape hanging in a convenient closet?