Maggie Gray used to be the Federation's most accomplished killer until they double crossed her. Twelve aliens from her mother's home planet of Atropia now threaten humanity, and Maggie must decide between the government that betrayed her or the potential extinction of humankind.
In the universe, there are two groups of Guardians—those that protect ideals and those that guard individuals. Jack Wagner is the Guardian appointed to Maggie Gray, a task she doesn't want or need. Unfortunately, she also has the misfortune of being the one person to have broken his heart.
Crossing enemies and allies alike, they work together to save the world from the Atropi Effect.