Young twin boys receive a boat of their own by a stroke of luck. It turns out to be very fast and they use their boat to help out their friends.

Hielke and Sitse, the twin sons of blacksmith Klinkhamer, are incorrigible rascals and the main source of entertainment in their sleepy (ficticious) Frisian town Lenten, where they especially take the mickey out of gullible braggart Gerbert. Their mother is embarrassed by their shameless pranks, father secretly sympathizes as they are often daring, honest and clever. The town is targeted by two fancy punks from the city. Shortly after the neighboring notary Bleeker takes is his city haughty niece Esther, he's killed himself in a terrible storm, during which the knaves help father rescue the doctor, who rewards them with his wrecked car, just what they need to put a new motor in a boat father can buy cheap for them after a row caused it to be badly damaged, but he manages to repair it. Then a posh frat from Leiden university descends on the town to hold its playful 'olympics', including a momentous swimming race, where cheaters and thugs get their comeuppance.—KGF Vissers