The Middleman (The Middleman #2)

"The Secret Recruitment Ultimatum"

Wendy Watson leads a secret double life: apprentice monster-smasher for a ridiculously secret organization by day, struggling bohemian artist by night, and with her first big case - the murder of mobsters by a ruthless assassin who may not be entirely human - Wendy must decide between a life of unbridled normalcy and the neverending conflict between the good, the bad, and the simply repulsive!