Follows a pair of childhood friends: Amelia and Archie. Archie has always kept his love for her a secret, but just as he builds up the courage to declare his feelings, Amelia falls for Billy Walsh, the new transfer student.

Depicting an epic 26th-century conflict between humanity and an alien threat known as the Covenant, the series weaves deeply drawn personal stories with action, adventure and a richly imagined vision of the future.