Marcy Thorpe is not exactly the kind of dog walker you want to give your house keys to. She's distracted, anxious, too curious, and has an attitude that always leads to trouble. But she's great with dogs and town elites hire her because, well, no one knows about her small transgressions. Her life is challenged by the responsibility of looking after her endearing, yet difficult, mentally-ill brother and non-coping mother.
Marcy's life is turned upside down when she loses her client's corgi, and her favorite dog, Sam. The search for Sam explodes on social media and becomes a national obsession, inspiring Sam's owner to fantasize about fame and fortune while aggravating Marcy's already growing anxiety over unwelcome ignominious attention.
Meanwhile, Sam takes time out to chat with the reader about his predicament, his plans to survive the "free market system" he has been forced into, and ideas concerning existentialism. Sam understands more than humans realize. This is of course why they can't find him.
Desperation to bring Sam home leads to a dilemma for everyone involved. Marcy has to make a choice, and the town learns something about this young woman who cares for their dogs. And everyone learns about what does and doesn't make a "good" person.