Brazilian writer Rex Ronis and his journalist friend Raimonds come to Estonia to explore the lives of smugglers in the Gulf of Finland for their latest novel. Posing as a thief, Rex infiltrates the ranks of the smugglers and gains the trust of their leader, Jan Kelgi. While preparing for another shipment of illegal liquor, several smugglers are apprehended by the Border Patrol. Rex, who is in love with the daughter of one of the smugglers, is determined to free them from the criminal clutches of Kelgi. "The Waves of Passion, Estonia's first international co-production and undoubtedly the most acclaimed of the fourteen silent films made in the country during the inter-war golden age, demonstrated the potential of this burgeoning film industry before the Great Depression overtook it.