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.
At the eve of Crimean war orphaned Regina lives with her grandmother in a small cabin near a lavish villa. As the summer approaches there is great anticipation of a big ball to be held.
Old Virtanen is a respected night watchman at a textile factory and a single father to his daughter Aino, who is about to graduate from high school. The heartless factory owner Kuusela fires Virtanen, who is forced to look for a new job. When Aino, who is in love with the manager's son Veikko, disappears after her graduation party, her father, who has fallen ill with worry, is overcome with despair.
