In 2805, Earth is abandoned and largely contaminated with garbage, with its people evacuated by megacorporation Buy-N-Large on giant starliners. BnL has left behind WALL-E robot trash compactors to clean up; however, all have since stopped functioning, except one unit who has gained sentience and is able to stay active using parts from other units. One day, WALL-E discovers a healthy seedling, which he returns to his home. Later, an unmanned spaceship lands and deploys an EVE probe to scan the planet. WALL-E is infatuated with EVE, who is initially hostile but gradually befriends him. When WALL-E brings EVE to his trailer and shows her the plant, however, she suddenly takes the plant and goes into standby mode. WALL-E, confused, unsuccessfully tries to reactivate her. The ship then returns to collect EVE, and with WALL-E clinging on, returns to its mothership, the starliner Axiom.
The Axiom’s passengers have become obese and feeble due to microgravity and reliance on an automated lifestyle, including the ship’s current captain, McCrea, who leaves the ship under the control of the robotic autopilot, AUTO. EVE is taken to the bridge, with WALL-E tagging along. McCrea is unprepared for a positive probe response, but learns that placing EVE’s plant in the ship’s Holo-Detector for verification will trigger a hyperjump back to Earth so humanity can recolonize it. However, AUTO orders his robotic assistant GO-4 to steal the plant to prevent this from happening.