In the year 2046, it's a new Earth - with new rules. Over thirty years after various alien races arrived on Earth, the landscape is completely altered, terraformed nearly beyond recognition. To the town of Defiance, on what used to be St. Louis, comes the mysterious Nolan (Grant Bowler) and his charge, Irisa (Stephanie Leonidas). As they settle into town - overseen by the mayor, Amanda Rosewater (Julie Benz) and filled with residents like the powerful Rafe McCawley (Graham Greene), enterprising lounge owner Kenya (Mia Kirshner) and the ambitious, alien Tarrs (Tony Curran and Jaime Murray) - events begin to unfold that threaten the fragile peace this border town has fought for.

The graduating class at Miss Aversham and Miss Cronstall's School for Girls find that they have - in defiance of the natural laws of probability - all blossomed simultaneously. Capitalizing on their unique status, and intent on teaching high school boys to NEVER take girls for granted, they issue a challenge to the boys of Easthill's rival private schools, Selby and Lancaster. The winner in a series of designated competitions will be awarded exclusive rights to the girls as prom dates. Like the capricious and meddlesome gods of Greek mythology, the ACS girls pit the boys' schools against each other in a (secret) Prom War.

On the eve of his high school graduation, unremarkable Will Kidman finally bonds with the girl he has long yearned for, reclusive Eliana Wynter. But he also discovers a dark secret from his past... that he is about to become a werewolf. Now, in an effort to fight destiny and save their love as well as their lives, they must battle not only Will\'s growing blood lust but an army of fearsome beasts bent on killing them... and then, us all.