Tanja Bulkova arrives in Finland under the name Toini Salonen and, with the help of spy chief Rosenberg, becomes the secretary of engineer Rautavuori and discovers the drawings of a secret invention.
The old man at the Eirtola house warns the new maid Eriikka about the fate of Jenny, the summer girl. Jouko, a university student from Eirtola, arrives home for the summer and begins to court the pretty maid. At the cattle shed, Eriikka finds a box, the contents of which she examines together with Pastor Tuomo Ahomaa. The tragic fate of Jenny, the summer girl, is revealed.
Pekka is given the task of renting a summer place, but real estate agent Aadolf Muikku tricks him into buying a villa.
