Buck Rogers: That Man On Beta was to have been the final Buck Rogers telefilm and to have ended the film series. Because, however, the series became a regular TV series, the film was never made, although a novelization of the same name was published.
It is the 25th Century, and the evil Draconian Empire has been repelled from Earth. Because the Draconian gene stocks are failing, Princess Ardala and Killer Kane abduct Buck while he is searching for descendants of his long dead family in the Wasteland. He is then taken to Beta, a planet where Ardala intends to use him as breeding stock for a new generation of Draconians. Eventually, Buck escapes from Beta and is able to return to Earth, where he reunites with Wilma Deering and Professor Huer. In the final scene, as described in the novelization, Buck is shown dancing with Wilma to the beat of a waltz.
Buck Rogers: That Man On Betanovelization (book, 1979)
Buck Rogers in the 25th CenturyWikipedia entry
Buck Rogers in the 25th CenturyIMDB entry