The Penguin decides to kidnap the daughter of the police commissioner and force her to marry him so he will have immunity. Clever but only if it works. Sure, Penguin was counting on Batman and Robin to make trouble but then Batgirl (yes, you heard right, Batgirl) comes onto the scene. And then there is Alfred, the keeper of secret identities. Gets involved by posing as a minister and Batgirl (aka Barbara Gordon) does not know this when she trusts him with her true identity. When she finds out later that he is not a man of the cloth, she commends him for taking the place of the real minister but makes him promise not to tell anyone.
The return of Batman, even a one day a week version is still something to be happy about and there is an excitement over the idea of the Dynamic Duo becoming the Terrific Trio. The episode's strength lies in the introduction of Batgirl, not in the story. Sadly, the stories don't get any better, for the most part, during this final season.
Another problem with the one episode per week season is that, as shown with the Penguin in this episode, the villain becomes more of a pain in Batman's side than an actual threat. Penguin kidnaps Barbara Gordon. The Riddler fixes fights. The Joker fixes a surfing competition. No quests to dominate Gotham or the world. The money schemes are pathetic and thus take away from the excitement of the show.