Even the term did not exist back then, but "De Kat" (the Cat), the eponymous protagonist of this TV series, is what we would today call an ecoterrorist. In a feline disguise, the Cat has vowed to put a stop to the environmental depredations of some greedy captains of industry by engaging in (by present-day standards relatively benign) acts of sabotage. The public's sympathy is mostly on the Cat's side, but things get really complicated when some people start to engage in copycat actions, and the real Cat has to figure out who is using his name and trademark disguise to pull off some daring capers of their own.