Cosi tells the story of Lewis, a young theatre director, who goes to a Melbourne mental institution in the year 1971 with his heart set on successfully directing a play using mental patients as actors. Little does he know that a mental patient named Roy has already planned to stage the Mozart Opera Cosi Fan Tutte. This leads to a power struggle throughout the play. Will they be able to set aside their differences and work together as a team? Will Henry, a shy old man, be able to conquer his fear and speak loud and proud in front of an audience. Will Cherry, be able to steal Lewis’s heart using food and violence? Or will Doug succeed in burning the theatre down before the show commences?