In Rome, Cora is a waitress at a club, walks people's dogs, sleeps with various men, kips with pals, and has a salty tongue. She also has a bruised history: her mother's suicide, her brother's mental illness. Ada, a dog-owning client, hires her to follow Ada's aged and courtly father every day. The dad, a retired philology professor, has a touch of dementia, sometimes forgetting where he is; Cora is to keep him in sight, phoning Ada if the professor has difficulties. On the third day, he takes a train out of Rome, and Cora follows on what proves to be a journey into her best and worst selves. She becomes his traveling companion, but what does he become to her?