Formentera; white-sand beaches, the crystal clear Mediterranean sea, unspoilt natural beauty and five friends looking forward to the holiday of their lives in this idyllic location. On their second day on the island, the friends discover a hidden cave nestled into the side of a cliff and decide to go in and explore it. Filled with excitement and adrenalin, the friends start to make their way through the countless passageways that make up the cave.
Before long, they realise they are lost. They try for hours to find the way back to the surface, eventually they decide to spend the night inside the cave and start searching again the next day, once they’ve had some rest. But days go by and they are unable to find their way out. Panic is starting to set in. They have no way of communicating with the outside world and no food or water... and the lack of light is tormenting them towards dementia.