Roswell focuses on four teenage alien-human hybrids living in Roswell, New Mexico. They are survivors of the 1947 UFO crash popularly known as The Roswell Incident. Max Evans, Isabel Evans, Michael Guerin and Tess Harding were sent to Earth as cloned replacements for the royalty of Antar, an alien planet. Their counterparts died in a war, and the "Royal Four" will one day return to Antar to save their race.
Central to the plot are the relationships between the hybrids and their human companions, particularly the one between Max Evans and Liz Parker. The three seasons follow the hybrids as they attempt to survive as humans and hide their alien sides, while trying to learn more about their alien powers, as well as figuring out how to get home.