Eager young radio reporter Teräsvuori stages a one-man burglary into the Helsinki Art Museum, recorded on tape for a later broadcast by his friend Laakso. Things go awry when a gang of real criminals overhear their plans and book their heist to coincide. Teräsvuori gets caught but escapes from police custody to start his private investigations together with female radio colleague Eila.
Tar Steam Princess Armada travels along Lake Saimaa to St. Petersburg and back during the years of Russian rule over Finland. The ship's crew gets tired of their sophisticated coffee maker and replaces her with Roma girl Veera, who has escaped from an arranged marriage. On the way back, mysterious passengers appear on the ship.
In the early 1800s, Finnish governor's daughter first detests but soon falls in love with Russian Czar Alexander I who has just taken Finland over from Sweden's rule.
The S/S Vellamo heads to Alexandria with Kaarina, the daughter of the ship's owner Hallerman, on board. As Kaarina trades places with the family's housekeeper Marja, first mate Yrjö takes a liking to Marja whom he believes to be miss Hallerman. Meanwhile Kaarina, pretending to be a member of the cleaning staff, starts getting close with lower ranking officer Kalle Aaltonen.
