100 fathoms below ... The depth at which sunlight no longer penetrates the ocean. 1983. The US nuclear submarine USS Roanoke embarks on a classified spy mission into Soviet waters. Their goal: to find evidence of a new, faster, and deadlier Soviet submarine that could tip the balance of the Cold War. But the Roanoke crew isn't alone. Something is on board with them. Something cunning and malevolent. Trapped in enemy...