Riley goes on a dog rescue story sure to win over Minneapolis viewers. But when the Twin Cities' latest murder victim is someone from Riley's past, she can't stay away. Kate Warner was her college roommate's sister. The killer's signature, a chalk outline of a winged angel, links him to a string of homicides across the Midwest. Which then leads Riley to the legendary Black Angel statue in an Iowa cemetery, and may lead to a twisted trap designed just for her by the angel killer himself.