Based on a true story, this suspense thriller stars Ellen Burstyn as Barbara, an English middle-class housewife, who allows a British secret agent (Alan Bates) to set up camp in her home for surveillance. Barbara is shocked to discover the feds are spying on her best friend and neighbor, an American (Teri Garr). As tension mounts in the investigation, Barbara battles with betrayal and uncertainty toward the mysterious friend she once trusted.