Bodies coated in clay squeeze through narrow rock passages, merging with the dimly lit cave walls, faintly illuminated by headlamps. The film observes a group of cavers and their varying motivations for embarking on an uncomfortable journey into the depths. In the furthest corners of the cave, which was discovered in 2019, lies a chamber filled with bizarre aragonite crystals. The most extraordinary of them is named “Hydra” by its discoverers.