Engineer Laciga is going away on a two-month work trip to Poland. His fiancée Alice is moving to Ostrava, where she has taken a job as a works doctor at a mine just to be with him. The news that the wedding will be delayed infuriates her, especially when Laciga leaves two minutes after her arrival. The energetic young woman moves into the hostel for single people and in revenge she deliberately blocks the bathroom for dozens of her fellow residents, all men. The chairman of the Factory Committee of the Revolutionary Trade Union Janecek and the mine director Kodet want to steer the otherwise very able doctor away from revenge and set her an important task. Alice is to test out the effects of regular drinking of milk as a calcium barrier against silicosis on a sample of miners.