Rudolf Buth, 86, can not stand the loneliness anymore. The widower resolutely decides to give up his apartment, where he lived for 45 years, to seek a new home. Pauline Pappert and Therese Heinze, both also 86, have been living in a shared flat for ten years. After a long time of looking for a female roommate, they are now willing to try a man. The first weeks of living together put everyone involved to the test. The documentary "Ménage à trois" shows how three people in old age find each other. The story of a new beginning with 85.