In an isolated Louisiana bayou community known as the Bathtub, six-year-old Hushpuppy lives with her father, Wink, in a ramshackle dwelling amid a wild, untamed environment. The community is cut off from the rest of the world by a levee, and its residents embrace a unique, boisterous lifestyle deeply connected to nature. Despite her mother's absence, Hushpuppy has a vivid imagination, seeing herself as a part of the cosmos and often listening to the heartbeat of the world around her. Wink is a rough but caring father, teaching his daughter to be resilient and self-sufficient in preparation for the day he's no longer able to protect her.

As the melting ice caps cause waters to rise and fearsome prehistoric creatures – the aurochs – to unfreeze and storm toward the Bathtub, Wink contracts a mysterious illness, further threatening his ability to care for Hushpuppy. The community faces the calamity of an approaching storm, which promises to flood their homes and disrupt their way of life. Unwilling to leave their land, the spirited Bathtub inhabitants choose to hunker down and ride out the storm, led by Wink's insistence on staying put. As the reality of environmental instability becomes more tangible, Hushpuppy's world is propelled into tumult, forging her into an indomitable force determined to survive the challenges of a changing universe.