Sarah and Maggie are sisters who are very different. Sarah has married and settled contentedly into small-town life. Maggie has spent fifteen years drifting around the world with a backpack. Now Maggie has come home to a dank, dull British winter, supposedly for just a few months. The Penn children are delighted to have their exciting aunt stay with them, but fate 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.