Interesting conceit – aliens have landed on Earth and have introduced an arbitrary programme of exchange. A knock on the door can herald a visit from an alien with a human ‘assistant’, and after that visit there will have been some exchange of property… or of people. A young girl finds her life increasingly disrupted as some exchanges, such as her mother’s old Lay Z Boy settee being exchange for some other furnishings, are ok to live with, but when her mother herself is swopped out….
