Nurse Florence Shaw is worried about her patient and friend, elderly widow Nora Selleck. When she encounters Nora in the market town of Stone seeming confused, Florence decides to pay her a visit in more familiar surroundings. But at Nora's house she meets Ben Evans, a mysterious young stranger who has befriended Nora. Who is Ben, and why is he encouraging Nora to miss her surgery appointments? Florence doesn't trust Ben. She's sure he doesn't have Nora's best interests at heart and is a threat to her vulnerable patient. But no one else, not even Nora's doctor, shares her concern. Until, one day, Nora suddenly disappears . . .