Joker is speaking to a "live" studio audience consisting of cardboard cutouts of Gotham's various public servants, including Batman and Robin.
Joker tells the camera that because he does not have a family to spend the holidays with, he has kidnapped Commissioner Gordon, Summer Gleeson, and Harvey Bullock to serve as one.
Using the Batcomputer, Batman accesses Gotham's electrical mainframe and pinpoints the location of Joker's signal by tracking power surges.
Robin uncouples the passenger cars, while Batman rescues the engineer just in time for the train to careen off the blown-up tracks and into the valley below.
Joker then gives the Dynamic Duo a clue to his hideout by broadcasting footage of Summer Gleeson opening a "Betty Blooper" doll.
Once they enter the factory, Joker, who has anticipated their arrival, sends out several giant robot nutcracker soldiers, which they dispose of rather easily.
Using his grappling hook, Batman ascends to a higher level and hides behind a pile of gigantic teddy bears.
At first, Donner and Blitzen are unsure of where the Dark Knight went, but they resume firing once they see his cape move across the bear pile.
Suddenly, a large pair of curtains are drawn back, revealing Joker, who has Gordon, Gleeson, and Bullock dangling over a vat of hot molten plastic.
However, being the Joker, he remains upbeat, singing "Deck the Halls", laughs hysterically, and ends the episode by saying, "Merry Christmas".
[3] Hamill, who found himself to be the biggest fan of the Batman comics among the cast, credited the laughs he had honed on stage in Amadeus with landing him the role.
It could easily be 15 minutes and far tighter...But it's a funny, charming piece of work, by no means a failure, and it provides some memorable lines and the beginning of two relationships—Batman and the Joker and Batman and Robin—that are essential to the show's development.