The special centers around Han and Chewbacca trying to return to the Wookiee planet of Kashyyyk for the celebration of Life Day. It is during this special that we learn that Chewie has a wife and a child. Which is still a little strange to think about.
I recall or at least I think I recall being pretty excited about the special airing. You have to remember that in 1978 one could not even watch Star Wars on their VCR. When I think back on that fateful day in 1978, I am not sure that I stayed awake for more than the first 30 minutes or so. In retrospect, that was probably for the best because over time, the Star Wars Holiday Special has become one of the most panned things ever created in the name of Star Wars.
For example, take a look at the SPECIAL GUEST STARS in the photo above. One really has to question what the pitch to executives must have looked like. Sure, let's have Be a Arthur play a gruff bartender at the Mos Eisley Cantina who bursts into song and argues with Greedo. There are so many things wrong with this idea that it makes the inclusion of Jar Jar Binks in Episode I seem like a really brilliant idea.