Maggie Gray was the Federation's most deadly assassin until they betrayed her. Now with a threat to human civilization, Maggie must choose between the Federation and twelve rogue aliens from her mother's home planet of Atropia.

There are two types of Guardians in the galaxy, those that guard an ideal, a way of life or some other abstract facet of life, and those that guard individuals; very important individuals who have a destiny to be fulfilled. Jack Wagner is assigned to guard Maggie Gray, a woman who has no use for guardians, is more than capable of taking care of herself, and the one woman who has broken his heart.

Together, they must save Earth from the Atropi Effect.