In Neil Marshall’s ‘Dog Soldiers’ a bunch of blokes went into the forest and scary shit happened. In this ferocious, blood-drenched follow-up, a bunch of women drop into a cave system in the Appalachian Mountains… and scary shit happens. It is, as Marshall acknowledges, ‘a sister movie’. A big sister: smarter, nastier and all grown-up. Once again, the heart-racing visceral horror comes thick and fast. This time, though, the all-female ensemble cast and complex group dynamics add emotional texture and psychological depth. Plunging the six female friends into claustrophobic darkness, Marshall mines a rich vein of subterranean terror. Trapped by a rock fall, they are attacked by slimy humanoid predators. Despite their translucent skin and sightless eyes, these creatures are highly evolved, using their heightened senses of smell and hearing to stalk their prey. Forced to dredge up their primal instinct for survival, the women tool-up with ice-picks or whatever else comes to hand, clambering over carpets of bones, plunging into pools of offal or hiding in crevices as the ‘crawlers’ try to sniff them out. As the women fight for their lives, the fault lines within the group are exposed: betrayals surface, tensions explode and loyalties disintegrate. They’re not just battling the snarling humanoids, but also each another. For Sarah (Shauna Macdonald) in particular – still fragile after the death of her husband and daughter in a road accident – this nightmarish mix of suspicion and fear threatens a slide into madness. Even more might have been made of this fractured group dynamic had the individual characters been better delineated, their relationships more sharply defined, their unspoken antagonisms more effectively explored. That said, one barely has time to register this shortcoming, as the adrenalised action drives relentlessly forward. Thanks to its skilful director, well-cast actors and talented technical team, this fiercely entertaining British horror movie has blood, guts and brains.