Beneath our feet lies a mystery. A complex underground network of mycorrhizal fungi keeps our ecosystem alive by exchanging nutrients and carbon with almost all plants on Earth. Remarkably, no one knows exactly how these sophisticated and ancient systems operate, or how they are affected by climate change.

The Underground Astronaut follows evolutionary biologist Toby Kiers, named one of the 2022 TIME100 Next Innovators, on her quest to map the world’s fungi networks and understand their behaviour before it’s too late. A fragrant and urgent journey underground. “No fungi, no future.”