The Flood opens in Louisiana during a powerful hurricane that brings torrential rain and rapidly rising floodwaters. Law enforcement is stressed, roads are impassable, and amid the chaos a prison transport van carrying inmates must divert its route. The storm forces the officers to seek shelter, and they end up at a nearby sheriff’s station. The building is supposed to be a temporary safe haven while the highway clears.

At the station, Sheriff Jo Newman is already handling her own troubles: deputies trying to manage flooding, rising tensions with staff, and the constant threat that the infrastructure may not hold. Into this fraught environment arrive five violent felons in transit, handcuffed, under guard by police officers. The prisoners are to stay until the weather eases. Unbeknownst to Jo, another group of criminals is tracking the transport—one of their own is inside the prison van and they plan a daring rescue.

As the station becomes inundated with water from the hurricane, unforeseen danger emerges. Floodwaters breach barriers, and a horde of giant, hungry alligators swept along by the storm finds its way into the building. The lawbreakers, guards, and staff are now trapped together in rising water with these deadly predators. In this setting, old conflicts and rivalries between inmates, guards, and criminals are forced aside as survival becomes the overriding concern.

Amid the growing carnage, Sheriff Jo tries to maintain order, protect innocents, and negotiate threats coming from two fronts: from both the human criminals attempting escape or control, and from the alligators that attack indiscriminately. One of the inmates, Cody, reveals more about himself: once dismissed from the military, he joined the criminal group, but as events worsen he begins to regret his choices. His complex loyalty and courage become key in later moments.

In the film’s climax, Jo and Cody make a desperate bid to flee through air ducts as the lower levels of the station flood and more gators close in. The criminal mastermind Rafe resurfaces, trying to use Cody as leverage to recover stolen money. Jo refuses opportunistic help, sets off explosions inside the station to kill many of the alligators, and confronts Rafe in a final showdown. There are heavy losses, and many characters perish.

In the end only Jo and Cody survive. Jo decides to officially identify Cody as one of the criminals who died in custody, giving him a chance at a new life. The stolen money subplot remains only loosely resolved, with hints of possible further consequences but also Jo’s implicit integrity: she appears not to claim the money for herself. The film closes on this fragile survival—bloodied, traumatized, but alive—and with the suggestion that heroism, even imperfect, matters when everything else is failing.