She used to work for the U.S. government, but very few people ever knew that. An expert in her field, she was one of the darkest secrets of an agency so clandestine it doesn’t even have a name. And when they decided she was a liability, they came for her without warning. Now, she rarely stays in the same place or uses the same name for long. They’ve killed the only other person she trusted, but something she knows still poses a threat. When her former handler offers her a way out, she realizes it’s her only chance to erase the giant target on her back. But it means taking one last job for her ex-employers. To her horror, the information she acquires only makes her situation more dangerous.

In Stephenie Meyer's first book for adults, alien "souls" have taken over the minds and bodies of humans. Melanie Stryder, a captured rebel, resists the takeover of her mind by Wanderer, the soul implanted in her body. Under the influence of Melanie's emotions, Wanderer is compelled to search for Melanie's love Jared and brother Jamie, who are still in hiding.