After a serial killer imitates the plots of his novels, successful mystery novelist Richard "Rick" Castle receives permission from the Mayor of New York City to tag along with an NYPD homicide investigation team for research purposes.

Placed in a foster home that doesn't allow pets, 16-year-old Andi and her younger brother, Bruce, turn an abandoned hotel into a home for their dog. Soon other strays arrive, and the hotel becomes a haven for every orphaned canine in town. But the kids have to do some quick thinking to keep the cops off their tails.