Batman (1966) - Season 03
In season 3 opener, the Penguin plans to gain immunity from the law by becoming the police commissioner’s son-in-law. He kidnaps Commissioner Gordon’s daughter, Barbara, and threatens her into agreeing to marry him. Unknown to him, Barbara Gordon has a secret crime fighting identity, Batgirl. Alfred learns of her secret when he is brought to Penguin’s hideout instead of a preacher, and Batman and Robin realize just how valuable their new ally is when they find themselves hopelessly strung up in Penguin’s lair.