After four children and their mother flee to America to escape their father, they take refuge in the mother’s family home, a dilapidated country estate where they can hide from the world. Soon afterwards their mother passes away and the siblings are left to fend for themselves until the eldest Jack reaches his 21st  birthday and so can legally inherit the estate and prevent them from being separated into foster care.

For much of The Secret of Marrowbone it’s a low-key and mildly engaging gothic drama, to the extent that the entity that may or may not be scrabbling in the attic is an issue so minor it’s barely a distraction. This is quite surprising given that writer-director Sergio G Sánchez was previously the scripter for insidious Spanish horror The Orphanage, but it’s made up for with a pervasively sinister atmosphere created by the home of crumbing edifice, creaking floorboards, overgrown gardens and cracked mirrors.

Their only connection to the outside world is Allie, a girl living on a nearby farm with whom they quickly become friends and Jack develops a fledgling relationship. As well as being English children in America, their disassociation is furthered by their looking somewhat out of time, as despite the story being set in the late ‘60s, the siblings inexplicably dress like it’s the early ‘20s.

When the story remembers to mention it, the looming spectre of exactly what it is they’re running from threatens to be revealed to the town at large, and in particular the sleazy lawyer dealing with the estate’s inheritance transfer. The moments featuring flashes of the something that’s scratching inside the walls are suitably creepy, and if there had been more of a focus on that, the film as a whole might have had something compelling to drive it.

The principal problem is the twist at the core of the story. The persistent issue with films whose plot hinges on one significant development is that unless it’s something spectacular it runs the risk of completely undoing any grace it may have built up. Unfortunately, this is exactly what happens here, and the point at which Marrowbone unleashes its grand revelation is the moment it all falls apart.

The twist doesn’t hold up to the mildest scrutiny, and the more you think about it and realise the extent to which it undermines everything to have thus far occurred, the angrier it will make you. It approaches Shyamalan levels of obnoxious bullshit, both in terms of the nonsensical twist itself and also its smug declaration being blissfully ignorant of the vast gulf between the perceived level of intellect and the reality. It erroneously believes it inspires you to rethink everything you’ve previously seen, and it’s a small mercy that we’re not forced to endure a montage of scenes from this new perspective.

The Secret of Marrowbone is most of a watchable if somewhat underwhelming drama with horror grace notes, but its arrogant complacency in failing to properly set itself up to remain plausible after it drops its ludicrous bombshell makes it a prime example of how to do such things wrong.

The Secret of Marrowbone / Cert: 15 / Director & Screenplay: Sergio G Sánchez / Starring: George Mackay, Anya Taylor-Joy, Charlie Heaton, Mia Goth, Matthew Stagg, Kyle Soller / Release Date: July 13th

Expected Rating:  6 out of 10