Marinette, Adrien and their friends want to actively fight plastic pollution in Paris. But at only their own scale, the task seems just too enormous. It occurs to Marinette that they should try to fix the problem at the root, by trying to convince the largest plastic manufacturer in person to change his habits. But the heroes will meet an opponent in plain clothes, more fearsome than even some supervillains. And what if, on top of that, Monarch decided to akumatize the baron of plastic?