A fictional exploration of human relationships, this film follows the life of a couple through various trials and challenges during their relationship. Berta, fed up with being ill-treated by her husband, decides to leave him. Antonio replaces her with a robot, but the substitute does not satisfy him. The machine is very submissive, just as Antonio wanted, but it is also permanently smiling. He is dissatisfied with its constant grin and would like the machine to resist a bit. He soon finds out from the designer that it is hard to achieve a balance between submissiveness and resistance, so Antonio asks his wife to come back. Eventually she returns, but events take a surprising turn.