Actor Romola Garai (Atonement; BBC’s The Hour) makes an impressive feature filmmaking debut with Amulet, an ambitious slice of slow-burn horror.

Set in modern-day London, the film offers viewers the exciting challenge of piecing together the dreams and reality of Tomaz (Alec Secareanu, God’s Own Country), a refugee of ambiguous Eastern European descent. Conveniently revealed in chronological order, the visions from his military past occur in gorgeously shot, thick woods and the crisp visuals contrast nicely with his grimy English homelessness and all that follows.

Still haunted by his history and the role that war-fleeing fellow townsperson Miriam (Angeliki Papoulia, The Lobster) played in it, Tomaz is recruited by a nun (Imelda Staunton, Dolores Umbridge from the Harry Potter films) to live with 30something Magda (Carla Juri, Blade Runner 2049) in exchange for home repairs.

That Tomaz doesn’t consider Magda’s sick mother wailing and knocking around in the blacked-out attic to be a deal-breaker all but justifies the supernatural troubles heading his way, but Garai takes her time building suspense, dropping just enough hints through facial expressions and close-ups on objects that typically don’t receive such attention to suggest that things are not well.

The subsequent action can feel plodding and frustrating in the moment, mostly due to the limited cast size and sparse dialogue, but is elevated by an increasing amount of freaky imagery — demonic hairless bats, anyone? — and disturbing body horror.

Garai lenses Tomaz’s downward spiral with a welcome steady hand, and while her script wallows in excessive exposition at critical final-act junctures, the parallels drawn between Tomaz’s isolated times with appealing women — which prove to be far more connected than he realizes — are clever and the answers still leave viewers with plenty of mysteries to solve on their own.

Once the truths are laid bare, Amulet further reveals that it too is far more than it initially appeared. Rather than merely a creepy, low-budget horror flick, Garai’s film winds up being a poignant, metaphor-rich exploration of sins and penance, and the role of an unusual sisterhood in punishing evil men.

Grade: B. Rated R. Available to rent starting July 24 via Grail Moviehouse

(Photo: Magnolia Pictures)