The dentist of the provincial town of Upper Yamki made an unexpected scientific discovery by finding the thirty-third tooth in the patient’s oral cavity, Ivan Sergeyevich Travkin. Travkin, exhausted from pain, was taken to Moscow. Ivan Sergeyevich first becomes a patient of a madhouse (thanks to envious persons), and then — a hero of a scientific international conference and, finally, a patient of a dentist professor Bruk.

1918 year. A woman commissar has been appointed from the Central Committee of the Bolshevik Party to the Russian warship Gromoboi, which is ruled by anarchist sailors. The leader of the ship is the anarchist Vozhak. The Commissioner was instructed to reorganize the naval detachment into the First Sailor Regiment. She faces a difficult task: to win the authority of the sailors and eradicate anarchy. Of the remaining officers on the ship — lieutenant Bering, who served in the tsarist fleet on the battleship "Emperor Paul I". He must become the commander and, together with the sent commissar, lead the regiment to the front in the Black Sea region.