Three Arab smugglers embark on a dangerous mission in the heart of a Middle Eastern desert, where their aim is to hunt for spiders. However, the situation turns grim when one of them, after dousing a spider nest with poison gas, ends up getting bitten. As more spiders burst from their nest, chaos ensues, leading to one smugglers’ demise at the hands of his companion, who uses a machete to make the harsh decision to end his suffering. The surviving smugglers manage to escape in their truck, but the horrors don’t end there.
Meanwhile, a single spider finds its way to a convenience store in Paris, catching the eye of Kaleb, played by Théo Christine, a sneaker dealer and exotic animal enthusiast. He unwittingly brings the creature home with him alongside a pair of earrings. Living in a vibrant multicultural suburb, Kaleb soon finds himself caught up in a whirlwind of events. He retrieves a bag of fireworks from a troublemaker, only to be reminded by his friend Mathys, portrayed by Jérôme Niel, of his obligation to sell a pair of sneakers to Toumani, portrayed by Ike Zacsongo. Tensions rise with his sister Manon, played by Lisa Nyarko, over the decision to sell their deceased mother’s house, providing an emotional backdrop as Kaleb grapples with his responsibilities.
In a twist of fate, the spider escapes into the shadows of Kaleb's room just as he gifts Claudia, portrayed by Marie-Philomène Nga, the earrings during her farewell party. Unable to find the creepy crawly after the party, he is forced to snatch Toumani’s sneakers for the day, ultimately crashing in the living room.
The next day unfolds in a heated argument between Kaleb and his former friend Jordy, played by Finnegan Oldfield, alongside Mathys and Lila, Jordy’s girlfriend. The group is supposed to help with renovations on the house, but suspicions arise when xenophobic neighbor Gilles, played by Emmanuel Bonami, accuses them of drug dealing. The situation escalates when Toumani is bitten by the spiders that emerge from the sneakers. After multiple failed attempts to reach him, Kaleb discovers Toumani’s lifeless body, leading to panic as authorities lock down the building.
Gilles is insistent that Toumani fell victim to an overdose from the drugs he assumed Kaleb sold him, though Kaleb vehemently denies it. In a frantic moment, Jordy manages to kill a spider bothering Manon in the bathroom, only for a wave of spiderlings to emerge, leading to absolute chaos. By the time Kaleb confesses that he is responsible for the infestation, it seems too late. The group discovers that the spiders belong to the Sicariidae family, notorious for their deadly venom.
The urgency increases as the infestation spirals out of control, resulting in more residents disappearing. Gilles misjudges the perilous situation when he attacks them with a baton, only to be met with dreadful consequences. As they attempt to escape to the parking garage, they cleverly maneuver through infested hallways while utilizing the timing of hall lights to thwart the spiders. In a desperate attempt to save each other, Jordy gets caught in a web, urging his friends to abandon him for their safety.
Upon realizing that spiders are sensitive to light, Mathys uses the fireworks as a distraction to facilitate their escape to the roof. It’s here that Kaleb reflects on past grievances with Jordy and realizes their childhood friendship was severed too hastily. The group faces numerous obstacles, including confrontations with the police and personal sacrifices as Mathys, after being bitten, becomes a hero by charging into the fray.
Kaleb manages to reunite with Manon in the midst of chaos, where they patch up their differences, realizing the deeper bond of family. Just as the terrifying spiders close in, Lila shines headlights to create an opportunity for their escape, allowing them to break free from the monstrous grip of the infestation. In the aftermath, they witness their neighborhood crumbling, a stark reminder of the horrors they faced. Kaleb pays homage to his late friend by burying a shoebox filled with cherished memories, while taking a final look at the spider that dared to cross paths with them, whispering a silent goodbye as he blows it away into the unknown.
