Emily Webb thought life would go back to normal after she and pack-mate Spencer Holt killed the man who tried to murder them and their fellow 'Deviants.' Or as normal as it could be, after finding out she has nighttime superpowers . . . and she's a werewolf. But when Emily wakes up one night to find an otherworldly shadowman watching her, she knows the danger has only just begun.

Determined to find answers, Emily and Spencer, along with the third member of their pack - football player Dalton McKinney - set out to find the people who made them what they are, and why. And as Emily and her friends get closer to the truth, they realize they aren't the only ones in town with special powers: The most popular girls in school just might have a secret of their own - and they just might have it out for Emily.

But other kinds of Deviants will be the least of the pack's problems if they can't get their own powers under control. With each nighttime shift, Dalton's behavior grows more erratic, and Emily's transformations begin to evolve in mysterious ways. With shadowy beings stalking the Deviants at every turn, a mysterious company doing all it can to keep the truth hidden, and the secrecy of her strange new identity in jeopardy, life threatens to spiral out of control for Emily. And soon all these dangers will come together in one terrifying confrontation that may force her to make the toughest choice of her life.