Hannah Lewis and her friends meet at North Head one Friday night. Fuelled by alcohol and urban legend they explore the mountain’s old tunnel system, looking for rumoured military secrets. As they head back to the surface, an earthquake traps the group inside. Unearthly noises from deep in the tunnels show them they’re not alone.
One by one, Hannah’s friends are taken. Trapped underground with only the detritus of past wars as protection, the survivors must face the nameless threat stalking them through the darkness.
But what hunts them? Tales abound of a failed attempt to create a super solider during World War One, the hideous result walled up beneath the mountain. But the truth is even more terrifying.