Adamant

Few people know twenty-one year old Ada Fletcher is actually from another universe. After a devastating magical war tore apart her homeworld, she and her family were forced to defy the Inter-World Alliance and hide on the low-magic Earth. Stuck in a dead-end job in London, Ada has spent her life hiding her real identity and risking her safety to help others from her homeworld. Until she loses her job, is chased by a rampaging monster, and is arrested by the Alliance as a prime suspect for a murder she had nothing to do with. It really isn't Ada's day.

Kay Walker, grandson of the Alliance's late founder, expects to spend his first week as an Alliance employee chasing monsters out of the Passages between worlds, not solving his supervisor's murder or questioning a strange, fierce young woman he arrested in the Passages. Killer or not, she's hiding something, and the closer he gets to the truth, the higher the body count rises.

The last thing Ada wants is to help the infuriating Alliance guard who arrested her, but it soon becomes clear that the Alliance knows too much about Ada's magic. More, in fact, than she knows herself. Now she has to choose between loyalty to her family, and helping the Alliance save the Earth -- and the Multiverse -- from a deadly enemy.