The 1968 TV episode "Assignment Earth" had been the Season Two finale for the original Star Trek series, and was intended by Gene Roddenberry as the pilot for a spin-off series that never came to pass. Now, Byrne delivers the series 40 years after it would have debuted, recounting the adventures of interstellar agent Gary Seven and his Earth-born assistant as they covertly confront threats to the past so that they can save Star Trek's future. Byrne writes and draws the series, which steps one year forward with each installment, beginning with 1968, the year that the spin-off series would have appeared.