Star Trek: Phase Two\Star Trek: Phase Two was a planned television series in the mid-1970s based on the characters of Gene Roddenberry's Star Trek. The planned series was to describe the adventures of the Enterprise crew on a second mission after the completion of the first series.
The series would have included several new characters, such as Commander Decker, Ilia, and the Vulcan Lieutenant Xon.
Eventually, plans for a series were cancelled in favor of a movie - Star Trek: The Motion Picture - in which all of the characters made an appearance (however briefly). In the movie, Decker and Ilia appearred as major characters throughout the movie. Lieutenant Xon (now called Commander Sonak) appeared only for a few minutes and had a few lines of dialogue before being killed in a transporter accident.
Several scripts for the series were used in early seasons of "Star Trek: The Next Generation".