Twin brothers Sietse and Hielke watch their beloved boat being seized due to pollution. Meanwhile multiple animals are found dead at a care farm. The twins start a search for the suspects.

The Frisian town has the misfortune to be picked as The Hague's test case for fining any diesel engine in a vehicle over ten years old 20,000 Euros, so even the Klinkhamer twins' signature boat Kameleon is soon chained, but they get an alternative solar engine. Local Hidde's 'care farm', which houses mental cases, is about to close down as all its goats are throat-slashed. The boys can't believe any more than his minder that Nando, an animals-obsessed Down-patient, did it with a knife stolen from the butcher, despite his consistent confession. In both cases, constable Bart Zwart must reluctantly enforce, charging his sole deputy, cocky hunk rookie Fonger, with jail-guarding Nando. The twins put Zwart on the trail of smugglers Jochem and Andres, who installed a drugs lab in Hidde's barn.—KGF Vissers