In 2007, the New South Wales Government proposed a plan to use the water in Lake St James to help with water shortages in the city. After much fanfare the proposal mysteriously vanished and so the story begins In 2008, chasing rumours of a Government cover-up and urban legends surrounding the sudden backflip, investigative journalist Natasha Warner led a crew of four into the underground labyrinth. They went down into the tunnels looking for a story until the story found them. With unprecedented access to the recently declassified tapes they shot in the claustrophobic subway tunnels, as well as a series of candid interviews with the survivors, we come face to face with the terrifying truth. This never before seen footage takes us deep inside the tunnels bringing the darkness to life and capturing the raw fear that threatens to tear the crew apart, leaving each one of them fighting for their lives.