Transformers 2 follows the story of the Autobots and their human allies as they fight to protect Earth from the remaining Decepticons who survived the battle in the first movie. Sam Witwicky, who was instrumental in defeating Megatron in the first film, now finds himself at the center of a new battle as he unknowingly holds the key to the next stage in the Autobot-Decepticon war. The Autobots must protect Sam from the Decepticons, who seek to capture and use him to locate the Matrix, a powerful artifact that would give the Decepticons the power to destroy the sun.