Retreat keeps you guessing . At times you’re absolutely convinced that Jack is a psychopath, or in the best case scenario, delusional.
Retreat does a lot with very little. Some of that little is borrowed, as the film weaves together ideas from The Shining, 28 Days Later, and The Disappearance of Alice Creed, among others, And some of it is a function of director Carl Tibbetts' skill at ratcheting up the tension.
The story is deceptively simple. As Kate (Thandie Newton) and Martin's (Cillian Murphy) marriage is crumbling, they revisit a remote island retreat where they once shared happier times. Their withering union is full of secrets and lies, and in a rustic cabin where the only way to communicate with the outside world is an ancient CB radio, they’re forced to confront each other.
In the midst of Martin and Kate’s bitter exchanges -- they hurt each other in ways that only people who used to be in love can do -- an injured stranger washes up on shore and things take a turn. Jack (Jamie Bell) is an army private, and after he wakes up, he tells a harrowing tale of a rapidly spreading global pandemic, and insists they seal up the cabin and barricade themselves inside. It is unclear if Jack is telling the truth or completely insane. What is readily apparent, however, is that he is dangerous, and Kate and Martin placate him while they figure out what the hell is really going on.
The film keeps you guessing with them. At times you’re absolutely convinced that Jack is a psychopath, or in the best case scenario, delusional. Other times you’re positive that he’s telling the truth and that the outside world really is engulfed in a worldwide plague the likes of which you’ve never seen. As you're guessing, you're also observing the perplexing dynamic formed by Jack, Kate, and Martin. Jack, whatever his motivations, needles at the couple's insecurities and petty jealousies, exacerbating their individual fears, pitting them against one another. At different moments, each allies with Jack, and their changing loyalties enhances the current tensions and also exploits all of their preexisting relationship drama, generating a slow-building sense of dread.
This dread is embodied most obviously but not only by Bell, who infuses Jack with a quiet menace, explosions of violence never lurk far below the surface, and keeps you guessing as to his true purpose. Jack inspires a performance of courage by Kate, but you know that she's more emotionally fragile than she initially appears. On his surface, Martin is a generic milquetoast, an architect, an embattled intellectual rather than a man of action; he also reveals what you might be dreading, however. When backed into a corner, Martin is compelled to act, against the moral platitudes or even the physical limits he thought he believed in.
All three characters are pressed together in Retreat, which mostly takes place inside the cabin, closed off from Jack’s supposed virus and without apparent escape. Even if Kate and Martin can get out of the house, they are still on an isolated, wind-swept island, surrounded by frigid Atlantic waters, with no boat. Like other horror movies set in isolated cabins, this one uses the site to make visual internal states. As the trio feels increasingly claustrophobic, as their distrust and fear spiral out of control, the structure literally deteriorates around them. What begins as a quaint vacation cottage, transforms into a sanctuary, then eventually devolves into a barren prison. Whether the exterior reflects the interior or vice versa (or both) remains a resonant question.