The Chrono Unit - Monday Moody, #1

Working for the Chrono Unit isn't all bad. Despite the terrible coffee, the possibility of never emerging from a time or space rip, or the boring paperwork, there is the satisfaction of knowing that dangerous time travellers are kept in check. Except that CU officer Monday Moody is secretly a Traveller herself. In a world where time travel is either forbidden or exploited, Monday has plans to climb the corporate ladder and make changes.
That is, if she lives long enough to reach those goals. When the homicidal Traveller Blayze Caden, who also happens to be her childhood friend, is after her life, she forms an unlikely team to hunt him down. She also has to juggle the fact that a deaf girl, who is also a Traveller, shows up on her doorstep for help. Monday now has two secrets to keep. Hiding the truth gets harder as she's getting close to the mayor of Sheffield, an influential vampire who has ties to the UA and is at war with rebel Travellers, as well as when Blayze decides to try and out her in between murder attempts. Not only does she have to decide which secrets are worth fighting for, but also whose side she is on.