It's a good few months since I enjoyed something as much as I'm enjoying this.
Using a real historical mystery as its point of departure, it has it all:
Meticulous attention to period detail.
First-rate acting.
Wonderful sets.
Intense and complex character motivation.
An atmosphere of icy isolation, the arctic's vastness; the insignificance of the crew when faced by it.
A brooding sense of unease that builds and builds.
Enough horror and gore to placate the blood lust of the must ardent horror fan.