A group of friends, spending the weekend in a house in the isolated countryside, are attacked by a swarm of killer horseflies that feed on human flesh like piranhas. The group soon discovers that the only deterrent that can keep the insects away is THC, the main ingredient that makes up cannabis. Their only hope of survival is therefore given by the consumption of grass, with all the consequences that entails.
In a sparse and inhospitable land, the policeman Enzo Vitello, a man with a dark past, is obsessed with "Dostoyevsky", a serial killer whom he kills with a peculiarity: next to the body, the murderer always leaves a letter with his desolate and very clear vision of the world, of life and darkness that Vitello hears resonating in him.
