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.
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.
Liisa and the renowned composer Raimo Kaarna are fond of each other, but in Kaarna's family history, everyone does not accept the relationship. In addition, Liisa has her own doubts, and a secret that does not endure the daylight.
