Annihilation feels like it might be the most Alex Garland thing that Alex Garland has written. The writer's sixth screenplay - the second that he has directed - is the embodiment of all his most characteristic traits: it is far more interested in ideas than characters, it's infatuated with the scientific processes at the heart of its drama, it has a third act that goes way the hell off the rails. Different people will have different feelings about these quirks, but speaking for myself, I've liked or loved nearly everything he's touched, and even so, Annihilation has already made a solid case for itself as his best project to date.

Adapted with a free hand from Jeff VanderMeer's novel, Annihilation starts after all the dust has settled, to find that Lena (Natalie Portman) is the solitary survivor of a military expedition into an inexplicable, undefined Something called "the Shimmer", for want of anything else to call it. Looking like a giant, dome-shaped oil slick in the sky, the Shimmer has been growing for some three years, and several teams have gone inside it, but Lena is only the second person to ever come out, and the first who was psychologically composed enough to be able to describe her experiences.

From here, it's flashback time, as we just how Lena, a ex-military officer and current biology professor specialising in the nature of cancer cells, ended up entering the Shimmer. First, her husband Kane (Oscar Isaac) shows up after a year missing in the Shimmer, suffering from massive organ flashback. For this, Lena ends up held in a high-security military facility, Area X, where she is bothered by psychologist Dr. Ventress (Jennifer Jason Leigh) for information she doesn't possess. Eventually, she talks her way onto the latest team entering the Shimmer, to be led by Ventress, along with physicist Josie Radek (Tessa Thompson), paramedic Anya Thorenson (Gina Rodriguez), and geologist Cass Sheppard (Tuva Nuvotny).

Any attempt to describe the plot will make Annihilation sound like something very different than what it is, because the plot sounds very much like an action-adventure film about sci-fi monsters. This is not at all the film's interest, only its pretext. If you noted the way I mentioned that Lena's research is all about cancer cell proliferation? Well, that is the film's interest. It would be a bit obnoxious to say that Annihilation is "about" cancer, but it's closer to that than it is to being a monster hunt inside a beautifully-designed sci-fi landscape. The Shimmer is, itself, little more than a giant, beautiful malignancy on the surface of the world, expanding steadily and without anybody being able to understand what hell is going on or how to stop it.Β  The monstrosities found inside of it, once were hear the technobabble that explains them, are nothing more fanciful than the victims of malfunctioning cells, mindlessly reproducing without purpose or a plan. Cancer, in other words.

Thing is, the film isn't simply using its science fiction trappings as a metaphor for cancer, it's in turn folding cancer into another metaphor: it's a film about how we deal with death. It's giving away very little that the film doesn't make clear from the opening scenes on that Lena's four teammates are all going to die; the stakes, then, are less about survival and more about the drive towards survival. All four of the other women have, as it turns out, some reason to have given up hope, and they all four embrace their hopelessness; Lena alone elects to fight on.

I would hate to go into it any more than that: Annihilation deserves to be seen, and worked out, with as little interference as possible (particularly its strange, sad ending, which reminds me very much of A.I. Artificial Intelligence, in part but by no means exclusively because of its design elements). Besides, there's plenty else to love besides how demanding the film is of its audience's attention and ability to pick upon innuendo. It's gorgeously designed and shot, to begin with: production designer Mark Digby has created a world inside the Shimmer that looks at once decayed and pulsing with life, a natural environment gone ever so slightly mad and leaving behind a post-apocalyptic landscape of bright greens. Cinematographer Rob Hardy builds on this with a simple but hugely effective visual trick: everything outside of the Shimmer is muted and in soft focus, everything inside is bright and vividly sharp in the way only digital cinematography can be so sharp. It's a straightforward means of depicting the depression that clings to the team members' lives in the "real world",Β  which gives way to something more intensely felt inside this quasi-spiritual plane.

As beautiful as the film is, it's also sad and haunting, and this internal conflict is one that the filmmakers exaggerate and exploit. Throughout, Annihilation is vaguely "wrong", failing to cohere in ways that are barely perceptible but distressing far in excess of their size, like a small bit of grit in your sock. Barney Pilling's editing is a clear enough example: the film almost, but not quite, breaks some of the most essential rules of Hollywood continuity editing, most notably the sacrosanct 180Β° Line, which guides spatial positioning and eye lines. It also nudges against less cast-iron rules, like the one that says that you should always cut to make sure that compositions are in balance, and that the viewer never has to move their eye too far to land on the subject of the next shot; Annihilation is full of passages where you have to keep darting back and forth, and as small as that sounds, it ends being slightly exhausting as you watch, unable to ever feel quite comfortable that the film is going to go where you expect. Same thing with the music, by Geoff Barrow and Ben Salisbury, who also scored Garland's other directorial effort, Ex Machina: much of the soundtrack is droning sci-fi menace, but sometimes it makes a break for soothing folk and folk rock (Crosby, Stills & Nash's "Helplessly Hoping" puts in a key appearance), and little if any effort is made to notice the disjunctive audio landscape this creates.

The result is a film that's quietly, pervasively uncomfortable, even before it makes its turns towards body horror (sometimes over-the-top, in the case of a tableaux that feels like it was taken from H.R. Giger, sometimes so small as to seem peaceful and beautiful), and a particularly dark and distressing monster movie (the design of a mutant killer bear is especially striking and shocking, and further cements the film's symbolic treatment of cancer, in addition to being attached to a singularly unnerving audio effect). It is a film about the world gone wrong - be it because of the Shimmer, cancer, or just the sense that things are unfair and people suffer who don't deserve it - and it brings that sense of wrongness with it in every aspect of its construction. Christ knows it's not for everybody, and it's least of all for the people that the shameless, dishonest ad campaign was trying to reach, but for me, this is hands-down the best sci-fi feature since 2013's Under the Skin, and I'll remind you that it's been a terrific few years for cinematic sci fi.