The Cook family, once prosperous, is surrounded by a certain mystery. Rosemary, a university student, recalls that as a child she was a surprisingly sociable, even talkative child, but now she is withdrawn, has difficulty making contact with people, and is tormented by strange complexes. Her older brother Lowell left home long ago. The mother experienced severe depression, the father, a famous scientist, stopped working on an important project. And the reader does not know for a long time who Fern is, about whom Rosemary writes: “She was my twin, my funny crooked mirror, my restless other half.” Only by finding Fern and returning to her can members of the Cook family finally find themselves again.