In a distant future, Earth is abandoned and covered in garbage, the result of centuries of mass consumerism and environmental neglect. The human population has evacuated on giant spaceships, leaving behind waste-collecting robots to clean up and make the planet habitable once again. One such robot, a solitary Waste Allocation Load Lifter – Earth Class (WALL-E), has developed sentience and a personality over the hundreds of years of toiling away at its task. With only a pet cockroach for company, WALL-E spends his days compacting trash into neat cubes and salvaging objects of interest, dreaming of life beyond the desolation.

WALL-E's existence takes a sharp turn when a sleek search robot named EVE arrives on Earth, sent from one of the spaceships to find signs of natural life regenerating on the planet. Incredibly curious and smitten by the new arrival, WALL-E shows EVE his latest discovery, a small green plant, indicating Earth's slow return to viability. Intrigued but duty-bound, EVE takes the plant and automatically enters a standby mode, awaiting retrieval. Unable to let EVE go, WALL-E clings to the exterior of her transport ship as it returns to the human fleet, setting off on a galactic adventure that unbeknownst to him, could shape the destiny of both himself and humanity.