Liz Ortecho reluctantly returns to her tourist-trap hometown of Roswell, N.M., and reconnects with Max Evans, her teenage crush who is now a Roswell police officer. 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 sister, Isobel, and their friend Michael. Elsewhere, Master Sgt. Jesse Manes spearheads a long-standing government conspiracy—unbeknownst to his son, Alex Manes.

The anniversary of Rosa’s death reignites tensions as the town takes aim at Liz and her father, Auturo, for what happened on that fateful day 10 years ago. Meanwhile, Max confronts Michael and Isobel, who are concerned that his feelings for Liz will expose their secret. Elsewhere, Master Sergeant Manes’ attempt to convince Kyle of the alien conspiracy in Roswell takes an unexpected turn. Finally, Liz and Kyle make a shocking revelation about Rosa’s death.

In a series of flashbacks to 2008, secrets are uncovered about Rosa’s final day, Isobel’s mysterious blackouts and Alex and Michael’s relationship in high school.

Max and Michael find themselves at an impasse over how to deal with the 4th alien. Liz has a dangerous encounter with an unexpected visitor. Kyle spirals after uncovering a dark secret about his father’s death. And Michael is forced to make a difficult decision about his future.

While Liz is settling in to her new life and career in Los Angeles, Max , Isobel and Michael are figuring out if the stranger in the cave, with the familiar face, is friend or foe.