Blood Red Sky sets up expectations of an intense thriller with horror gimmickry thrown in for good measure between its title and the logline. Terrorists attempting to hijack a transatlantic overnight flight find resistance in the form of a vampire. It’s the type of plot that screams action-horror spectacle, yet this high-altitude thriller defies expectations from the start. A beating heart of familial love pumps through the veins of this intense horror-thriller with a vicious take on vampire lore.

Nadja (Peri Baumeister) and her ten-year-old son, Elias (Carl Anton Koch), board a flight from Germany to New York. She’s very ill and hopes the doctor in New York can cure her illness with an experimental transfusion. Violent terrorists hijack the flight straightaway, putting their lives at risk. Nadja’s determined to protect her son at any cost. When a particularly sadistic terrorist causes harm, it triggers Nadja’s inner monster, unleashing a perilous new fight for survival for everyone on board.

Director Peter Thorwarth, who co-wrote the script with Stefan Holtz, takes care in doling out Nadja’s story. It’s clear from the outset that she’s a vampire desperately searching for a cure, but her backstory and answers of how she ended up a bloodthirsty monster raising a charming, human son come in flashbacks over time. Nadja’s struggle to keep the evil within her at bay for the safety of Elias provides the backbone of the story, one that adds a surprising level of depth as the action and horror escalates at a steady clip. Though at a two-hour runtime, some stretches sag in energy.

This unique mother-son bond is compounded tenfold by Koch’s remarkable performance. Nadja may be a desperate mom that fiercely loves her son, but Koch imbues Elias with a precocious maturity. Elias’s unwavering love of mom adds a heartfelt, humanizing component. More profoundly, it adds a melancholic underpinning; Nadja slowly giving in to her inner monster by necessity doubles as a metaphor for a young child watching his mother succumb to a ruthless disease that renders her unrecognizable.

Nadja’s drive to keep Elias alive provides the stakes, and Thorwarth keeps applying pressure throughout. The filmmaker finds clever ways to maximize the limited space of the plane, utilizing just about every corner of it as each scenario adds a new obstacle to the mix. A feral Nadja isn’t the only problem the hijackers encounter, and all of it causes a ripple effect of catastrophe.

The vampire lore and design here are stellar. There’s nothing romanticized about the bloodsuckers in this story. The vampires within are primal monsters with one instinctual drive; to rip out jugulars and feed.

Thorwarth blends an intense thriller with blood-filled horror, then grounds it all with an emotional core that pulls at your heartstrings. Even when the hijackers fall into familiar stock bad guy tropes, it’s Nadja and her loyal son that keep the narrative so unpredictable. Blood Red Sky defies expectations by opting for a far more complex journey than the plot suggests. It delivers on its concept, bringing the entertainment by way of big spectacle thrills. But by handling its character development and vampire lore with care, Blood Red Sky is a surprisingly savage little gem that sticks with you.

Netflix releases Blood Red Sky on July 23.