An idyllic family vacation is interrupted by four strangers, each armed with an elaborate, medieval-looking weapon. The four demand entry into the rustic holiday home of Eric (Jonathan Groff), Andrew (Ben Aldridge) and their adopted daughter Wen (Kristen Cui). Having clocked the machetes and scythes, Eric and Andrew resist. But since one of the strangers is played by human battering ram Dave Bautista, it’s only a matter of time before they gain entry. And so director M Night Shyamalan sets the scene for a home invasion thriller with a difference: Eric, Andrew and Wen must, they are told, sacrifice one member of their small family in order to save the rest of humanity. But should they trust the motives of four individuals who seem to be undergoing a form of collective psychosis? Adapted from a novel by Paul Tremblay, Knock at the Cabin is initially slightly exposition-heavy – Bautista spends a great deal of time patiently explaining the plot. To his credit, he’s a gravely persuasive presence. But as the film’s bleak momentum builds, so does a tsunami swell of existential dread. It’s Shyamalan’s most contained and efficient picture in a while.