It does not go well: as they get lost in the depths and encounter flesh-eating humanoid monsters called Crawlers, the film descends (wink wink) into a bloody, violent fight for survival. Neil Marshall: Which is bizarre, because we were at pains to desexualise the whole thing. Once I’d made the decision to make them all women, I never really gave it a second thought. I said, “If that’s the film you want to make, I quit.” That’s the kind of stuff we were dealing with. Even now, it’s still very rare, certainly in the horror genre, to get an all-female cast.