It's time for the reckless guy Simion Cook to join the army. Having joined the airborne troops under the command of petty officer Petro Golovko, who is not indifferent to music, who organizes the vocal trio "Sineva", named after the initial letters of its participants: Moldovan Simeon, Armenian Nerses and Russian Vasily. And now the day has come when a new musical director, who turned out to be a charming girl Sasha, should arrive at the military unit. Who would have guessed that after the service, Simion would return home with a pretty bride...