In 1984, in the drought-stricken town of Namanga, Kenya, a young girl is found alone wandering the wilderness. Jack Ringtree is the one who brings her to the local school to learn more about her origins, while the town grapples with a brutal water shortage that has turned the landscape arid and tense. In a bid to secure a vital resource, Jack visits a nearby mining outpost, where the owner, Chris Tucker, brushes him off with a sharp rebuke. That same night, Lee Ringtree arrives in Namanga and shares a private, intimate moment with Jack, a fleeting respite amid mounting pressures and fear.
Shortly after, a local boy is kidnapped by a troop of chacma baboons, setting off a cascade of desperate efforts. The next morning, Claud Gagnon, one of the miners, is mauled by the same primate force, and the grandfather of the missing child calls for help from Jack and Chris. In response, Chris leads a group of miners and a cadre of Maasai women into the surrounding areas to search for the child. They discover both the child’s body and Claud’s, a brutal reminder of the danger closing in from the forest. The group retaliates by massacring a troop of baboons, while Jack documents the scene, capturing images as proof of what has happened.
Facing the crisis, Jack and Chris push for the evacuation of Namanga to Nairobi, hoping to bring in help to eradicate the baboon threat, but the local district administrator, District Officer Tshombe, dismisses their plea. Undeterred, Jack makes the long journey to Nairobi in search of someone capable of stopping the baboons, only to be met with bureaucratic indifference. Back home, Lucille, Lucille Gagnon and Claud’s widow, mourns the loss and contemplates leaving the country, while two electricians struggle to repair a broken telephone line as the danger outside grows more acute.
The tension peaks when Lee Ringtree is attacked by a baboon and narrowly survives, and when the mining outpost itself comes under siege, forcing everyone to flee or hide. Chris receives a report of a supply truck that has crashed about ten miles from Namanga, and he, Julius Odom, and Mitushi Uto head out to the crash site. Uto explores the area and discovers that almost everything has been looted. The trio manages to frighten off the baboons guarding the supply, and Jack, who stays behind at first, discovers the overturned truck and later rejoins them. The baboons return with renewed ferocity, forcing Chris, Odom, and Uto to abandon the site in a jeep and leave Jack to navigate his way out.
A dramatic turn arrives when Tshombe orchestrates an evacuation for Lucille, but a stowaway baboon on the plane triggers a crash that kills them all, a brutal twist that leaves the town reeling. When Chris returns, he learns that a local school has come under attack and sends Julius Odom and Mitushi Uto to help. Jack, resourceful and unyielding, bribes the baboons to create a distraction and escapes, hijacking an abandoned bus to reunite with Chris. The two drive to the school with the others and succeed in saving everyone inside.
With the town barricaded inside a fortified hotel, the miners stand guard and the community braces for further assaults. The teacher Linda is killed by a baboon that breaches the hotel, heightening the fear and urgency. Yet, as Chris and Jack hold the line, rain begins to fall, momentarily dampening the aggression of the baboons. The sudden downpour brings relief and, remarkably, helps break the drought that had gripped Namanga for so long. In the end, the town survives the siege, water returns, and a fragile peace settles over the once-desperate community.
