Max's life is placed in more danger than ever before when she is hunted by the one person who knows her better than anyone -- her clone. Though even the existence of this exact replica is news to Max, she quickly realizes the imminent danger from an individual who can get inside her head and infiltrate her life like no one else. Dealing not only with this new threat but also the disintegration of her relationship with Logan and Joshua's disillusionment over not being able to go out in public, Max must race against time to figure out how to stop this deadly enemy before it's too late.

Max begins to develop strange markings on her body while leading a transgenic resistance against White, when he attempts to capture one of her ""brothers"". However, the transgenics are stunned by revealed secrets about their ""father"" that threaten all that they believe and stir up many more questions. Meanwhile, the Terminal City dwellers mount a campaign to battle the humans hunting them down, and Alec learns why Logan has been keeping his distance from his former friends.