In the sixth golden retriever mystery, Dog Have Mercy, Christmas approaches and reformed hacker Steve Levitan tries to help a fellow ex-con now working at the vet's office in Stewart's Crossing. His curiosity, and the crime-solving instincts of his golden retriever, Rochester, kick in when liquid potassium ampoules are stolen from the vet and Steve's new friend is a suspect. Is this theft connected to a drug-running operation in North Philly? Or to a recent spate of deaths at the local nursing home? And can Steve continue to resist his computer-hacking impulses or will his desire to help others continue to lead him into trouble?