Based on

Movies like Naval Cadets III (1992)

There is a seven-year war, Russian soldiers are forced to fight for the interests of France and Austria against Prussia. The midshipmen continue to selflessly serve the Motherland. One is on an expedition, the other is at court, and the third is sent to Venice to hand over a jewelry box. In fact, there is a message in the box, on which the future fate of Europe and Russia depends!