In 1970, a team of Soviet scientists started drilling. For 28 years, they kept going… until after nearly 4,000 meters… they suddenly stopped. Because they’d found something unimaginable: Liquid water. A secret lake, down below all this ice, that had been completely sealed off from the rest of the world for 15 million years. How? And… is there something alive in there? Creatures that have been evolving separately from the rest of the planet for 15 million years?