The Artopi Effect
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.
In the galaxy, there are two categories of Guardians: those who defend ideals and those who defend individuals. Jack Wagner has been 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.