The most advanced scientific enterprise ever mounted, Sir John Franklin's 1845 expedition in search of the fabled North-West Passage had every expectation of triumph.

But for almost two years his ships HMS Terror and Erebus have been trapped in the Arctic ice. Supplies of fuel and food are running low. Scurvy, starvation and even madness beging to take their toll. And yet the real threat isn't from the constantly shifting, alien landscape, the flesh-numbing temperatures or being crushed by the unyielding, frozen ocean. No, the real threat is far more terrifying.

There is something out there in the frigid darkness. It stalks the ships and snatches men. It is a nameless thing. At once nowhere and everywhere, this terror has become the expedition's nemesis . . .