Sarah Penn and Maggie Reave are sisters, who are very different. Sarah has married kind, reliable Leo and settled contentedly into small-town life. Maggie, light-hearted and footloose, has spent fifteen years drifting round the world with a backpack. Now Maggie has come home, to a dank, dull British winter. Just for a few months, she says, while she learns Chinese for the next expedition. The Penn children are delighted: the boys revel in her tales of pamperos and pythons, and anxious fifteen-year-old Samantha is only too glad to have someone to help her with a pregnancy test. Even Leo, struggling with a precarious family bookshop, finds a use for his wayward sister-in-law. Fate, however, has an unexpected adventure in store; it rocks the whole family, bringing up dark shadows from their common past, and confronts Maggie with the hardest decision of her life.