 Problems for the happy couple ensue when Elsa, a bored housewife, suddenly appears unannounced at their door after leaving her cheating husband Thomas and their two children, and a menage-a-trois develops.Elsa immediately begins trying to dominate their lives.Alice wants the out-of-control Elsa, who disrupts their life by playing psychological games with them, to leave, but then suddenly changes her mind, unable to bring herself to throw Elsa out.