There are a fair number of scares in The Gift, but the most shocking part of the film isn’t the sudden appearance of a mysterious package or a creepy guy popping out of the shadows; it’s the way the film’s resident creepy guy is slowly revealed as a man with a broken heart and genuine feelings. When he’s introduced, Gordo (Joel Edgerton) gives off an unsettling vibe. His conversations are awkward and stilted; his clothes make him look like a time traveler from the early ’90s. But the more time The Gift spends with him the less threatening he appears — or at least the more threatening his supposed victims become.

Those victims are Simon (Jason Bateman) and Robyn (Rebecca Hall), a married couple freshly relocated from Chicago to Southern California. They’re out shopping for home goods to fill out their new mid-century modern house in the Hollywood Hills when Gordo spots Simon, an old high-school classmate, and reintroduces himself. They exchange a few pleasantries, take Gordo’s phone number, and go their separate ways. But then gifts start arriving at Simon and Robyn’s, and when the couple is slow to thank Gordo for his thoughtfulness, he stops by for a visit. Despite Simon’s barely masked contempt for his old buddy, who he derisively (but accurately) calls a weirdo, clingy Gordo refuses to leave them alone.

The astute horror fan might think they can anticipate what comes next; likely something in the vein of Fatal Attraction or One Hour Photo, where a deranged sociopath infiltrates a happy family and slowly tears it apart through manipulation and violence. But The Gift, which was written and directed by Edgerton, repeatedly subverts viewers’ expectations. After a formulaic intro, it suddenly veers off the familiar track, eschewing most typical slasher stuff to peel back the emotional and psychological layers on each of the main characters, none of whom are entirely who they initially appear to be. Ironically, the further The Gift gets from traditional (and sensational) horror-movie tropes the more interesting (and exciting) it gets. The Gift’s story might be the most pleasantly unpredictable of the 2015 summer movie season.

A busy actor (and occasional screenwriter of similarly twisted thrillers of marital discord like The Square and Wish You Were Here) Edgerton proves himself a smart and capable director, particularly of actors. The Gift is Hall’s best work in years, and a notably interesting use of Bateman, whose smarmy comedic persona proves an effective and unnerving cover for Simon’s sinister side.

Edgerton’s camerawork and editing choices aren’t flashy, but the Great Gatsby and Exodus: Gods and Kings star already understands how to express ideas with subtle visual cues. Simon and Robyn’s house, for example, with its floor-to-ceiling windows not only serves as an ideal setting for a horror movie about the terrifying things that lurk in the dark, its glass walls speaks to the movie’s themes of transparency and secrecy in a troubled marriage.

The Gift’s final act delivers yet another narrative shock, though not necessarily a welcome one. After spending most its middle third burrowing deeply into the characters and their respective pasts, the film pulls back, and winds up satisfying many of the surface conventions of the genre it had previously upended. Still, there’s enough here to recommend, both as a disturbing drama about human nature and as a calling card for Edgerton, who could have a bright directorial career ahead of him if he can keep delivering movies that zig when audiences expect them to zag. For cinephiles, little surprises like these are the best gift of all.