When Emery Whitehill was 6 years old, an alien spacecraft crash-landed in her small town and she met Roman, a 6-year old Atrian boy, who sought refuge with her before being taken away by the authorities. Ten years later, the two are reunited as the first group of Atrian teens is about to enroll in high school in a widely scrutinized social experiment to see if humans and Atrians can live in peace. Both Emery and Roman are surprised at the small-mindedness of their respective communities. Roman's sister, Sophia, is excited to make new friends, but their fellow Atrians, Teri and Drake, openly distrust all humans. The human students are equally wary of the aliens, especially the school's queen bee Taylor. Kind-hearted Grayson is drawn to Emery but has a secret that could threaten their new friendship. Only two of Emery's friends - Julia and Lukas, seem able to accept the Atrians. Emery and Roman find themselves drawn together again but outside forces work hard to keep them apart.