Unlike all the other sleazeballs and one-night-standers out there, this one seems to want a committed ­relationship, and to be a stepfather to the kids – who, heaven knows, could use a man's strong and stabilising influence. Then, about six months after he has insinuated ­himself into the family home, ­something snaps and he murders all of them, and moves on to a new city far away: we see the MO in a gruesome opening credit sequence. Dylan Walsh plays the killer, David, who now has a divorced woman in his sights, but ­interestingly twigs slightly too late that along with her two unthreatening little moppets, she has a big, tearaway older boy just back from military school – and this son doesn't like the look of mom's new friend one bit. I particularly liked David's excruciatingly embarrassing yet shrewd counter-ploy of asking his stepson to be his best man at the wedding. It's all very silly, but effective popcorn entertainment.

These are films that boast outlandish premises, fantastically unhinged villains and kitschy line-readings, but mine a deep seam of contemporary anxiety about the disintegration of the family unit. Marital disharmony and divorce, they say, will eventually lead to knife-wielding paramours and crazy nannies rigging greenhouses for glass shower finales.

In The Stepfather the greenhouse is replaced by an attic, the butcher’s knife by a buzz saw, but the logic is still the same. “Marriage: good; divorce: bad,” the movie says, as it depicts a sassy mom, Susan Harding (Sela Ward), freshly divorced and struggling in an Oregon supermarket with two uninterested children. There she meets a mild-mannered widower, David Harris (Nip/Tuck’s Dylan Walsh), who, in a genuinely creepy opening sequence, is seen brushing, shaving and attending to the minutiae of male grooming while surrounded by the etiolated corpses of his previous victims. David’s modus operandi is never made entirely clear, although he appears to be driven by the need to replicate the perfect 1950s-style family, and when this proves impossible, he slaughters everyone in the house.

Typically, Susan is wowed by his sensitive New Man persona (he talks a lot about feelings and family) and has soon taken him into the marital bed and up the aisle. In fact, she loves him so much that she doesn’t think to question the six insanely large and padlocked cupboards he builds for himself in the basement. “Men, eh?” her besotted smile says as David emerges from the basement, wrapped in a tool belt and sinisterly sweating.

David’s plans, however, to dominate the Harding family are soon scuppered by the return of eldest son and reform school brat Michael (Penn Badgley, channelling Andy Garcia). Michael is raw and impulsive, and has a girlfriend (Amber Heard) who wears only bikinis. He is the primal masculine Yang to David’s effete and slippery Yin. “To you and me, father and son!” says David to Michael, raising a toast. “Step-father,” Michael counters coolly, flinging down the gauntlet.

The stage is thus set for an epic battle of wills, one in which Michael will fight for the soul of his family while David will start murdering anyone — including a nosy next-door pensioner and Susan’s ex-husband — who dares to question his parenting skills.

All this, of course, is played with deadly straight faces by a quietly effective cast. Walsh, in particular, guided by his Nip/Tuck director Nelson McCormick (this is the latter’s first film) is especially effective in the early scenes at conveying subtly unhinged. “So good to finally meet you,” he gushes to Michael on their first encounter, while tellingly shaking his head in horror. Later too he somehow manages to engender sympathy for the plight of a mass murderer on the verge of detection. And if the movie’s attic-bound climax is a little predictable and the plot holes rather gaping, The Stepfather, unlike many of its more prestigious A-class competitors, is never less than entertaining.