When Liz Ortecho reluctantly returns to her tourist-trap hometown of Roswell, New Mexico, she 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 Sergeant Jesse Manes spearheads a long-standing government conspiracy - unbeknownst to his son, Alex Manes, who has recently returned from service overseas with emotional and physical injuries. The politics of fear and hatred that run rampant in Roswell threaten to expose Max and his family and could endanger his deepening romance with Liz... as well as their lives.
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.
After uncovering some unsettling information about Max, Liz runs a series of tests to see what his powers may be capable of. Michael and Isobel take matters into their own hands after learning that Liz may be getting too close to Max. Liz enlists Maria's help as she goes on a scavenger hunt across Roswell to uncover more about Rosa's final days.
Fearing that his identity will be uncovered, Max is conflicted when a town-wide power outage leaves patients at the hospital in need of help. Meanwhile, Liz turns to Kyle after learning details about the night Rosa died. Elsewhere, Isobel and Michael come up with a plan to deal with Liz, and Master Sargent Manes seeks help from an unlikely source.
Max and Michael begin to worry about Isobel after a series of mysterious blackouts cause her to spiral. Liz turns to Grant Green for help when she learns that he may have witnessed something strange on the night Rosa died. Kyle and Alex uncover a secret that Kyle's father had been keeping from everyone.
Secrets are uncovered about Rosa's final day, Isobel's mysterious blackouts and Alex and Michael's relationship in high school.
After uncovering a devastating secret about Rosa's death, Liz takes matters into her own hands to protect herself and those around her. However, her plans are sidelined after a day with Mimi, Maria and Alex leads to a new revelation about Rosa. Elsewhere, Max takes aim at Wyatt, while Cameron decides whether she's going to help Sergeant Manes.
With Isobel's life hanging in the balance, Liz and Michael frantically search for a way to help her. Max turns to his mom Ann about the origins of the alien symbol. Finally, Alex turns the tables on Sergeant Manes.
Max and Michael travel to Texas to visit a faith healer, who may be able to shed some light on the alien symbol Max has been researching. Meanwhile, Maria and Liz pay a visit to the same faith healer in hopes of finding a cure for Maria's ailing mother. Elsewhere, Alex and Kyle look into what Sergeant Manes may be hiding.
Frustrated by her inability to remember what happened the night Rosa died, Isobel turns to Liz for help regaining her memories. Elsewhere, Max and Cameron investigate a series of strange deaths in the town, while Sheriff Valenti reveals information to Kyle about his father.
As the town prepares for the UFO Emporium Re-opening Gala, Liz and team find themselves on a collision course with an unlikely enemy.
When a major revelation comes to light, Max, Michael and Isobel clash over how to deal with the fallout. Elsewhere, Alex uncovers a secret about Project Shepard and enlists Kyle and Michael's help looking into it.
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.