The plot introduces the idea that among the Tenctonese slaves, there was a resistance movement called the Udara who were implanted with hypnotic suggestions to act as sleeper agents. Now, here on Earth, someone has found a way to activate these sleeper agents, and send them out as assassins. It is the fifth and final television film produced to continue the story of the television series Alien Nation.

References:
https://en.wikipedia.org/wiki/Alien_Nation:_The_Udara_Legacy