A stranger takes over a role in a play, leaving the rest of the cast to ponder his motives. Two minutes into the second act, there is a knock on Nicolas Boehlmer’s dressing-room door, just as he’s smoking his last cigarette before having to go back on stage. . and, without thinking, he says,“Come in,” still in character. He quickly finds himself bound, gagged, and stripped by a man who appears to be his mirror image: costumed in the same wig, make-up, and clothes. Nicolas is powerless to prevent his usurper from going out and playing his role — with increasingly ridiculous consequences. Is this “upstaging” the act of a depraved amateur? Sabotage by a rival? A piece of guerrilla theater? A political statement? Whatever the cause, Nicolas and his fellow actors soon find their play — and their lives — making less and less sense, as the parts they play come under assault by this irrational intruder