Mushrooms have hardly been researched. They are among the oldest and most diverse life forms on our planet. Plants were only able to develop through fungi in primeval times. They are at home everywhere: in the earth, in the air, in our bodies. And they form huge networks. They are intelligent even though they don't have a brain of their own, they make decisions and trade in the plants they live with. They possess insect bodies and turn them into zombies. Are mushrooms the secret rulers of the planet?