More than maybe anywhere else on Earth, "Roswell, New Mexico" is ground zero for those who seek proof that aliens exist. Roswell native Liz Ortecho left it all behind 10 years ago, after the death of her beloved older sister, Rosa. But with her father ailing, she reluctantly returns to her tourist-trap hometown to move back in with him. When Liz arrives, she reconnects with Max Evans, her teenage crush who is now a Roswell police officer. Their chemistry is instantly electric. But Liz soon discovers a shocking truth: Max is an alien who has kept his unearthly abilities hidden his entire life, along with those of his otherworldly siblings, Isobel and Michael.

As the two grow closer after a decade apart, Liz finds it difficult to keep the truth from her best friend, Maria De Luca, and her trusting high school ex, Dr. Kyle Valenti. Also hiding their extraterrestrial origins are Isobel and Michael, with Isobel not even revealing the truth to her husband, Noah, and Michael keeping his identity hidden beneath a bad-boy exterior of hard living and casual hookups. Meanwhile, a long-standing government conspiracy spearheaded by Master Sgt. Jesse Manes, along with the politics of fear and hatred that run rampant in Roswell, threatens to expose Max and his family, and could endanger his deepening romance with Liz... as well as their lives.