Optimus Prime, leader of the benevolent Autobots, narrates the collapse of the Transformers' home world, Cybertron. It was destroyed by war between the Autobots and the malevolent Decepticons, lead by Megatron in his quest to get hold of the AllSpark. The Autobots want to find the AllSpark so they can use it to rebuild Cybertron and end the war, while the Decepticons want to use it to defeat the Autobots and take over the universe. Megatron had managed to locate the AllSpark on Earth, but crash-landed in the Arctic Circle and froze in the ice. After stumbling upon his frozen body in 1897, explorer Captain Archibald Witwicky accidentally activated Megatron's navigational system and his eye glasses were imprinted with the coordinates of the AllSpark's location, an incident that left him blind and mentally unstable. Sector 7, a secret government organization created by President Herbert Hoover, discovered the AllSpark in the Colorado River and built the Hoover Dam around it to mask its energy emissions. The still-frozen Megatron was moved into this facility and was used to advance human technology through reverse engineering. In the present day, the Decepticon known as Blackout arrives in a U.S. military base in Qatar to find the location of Megatron and the AllSpark. He tries to hack into the files of the computer base, but is stopped by Captain William Lennox and his team. Back in the United States, Captain Witwicky's descendant Sam Witwicky buys his first car which turns out to be the Autobot scout Bumblebee, who tries to help him woo his crush Mikaela Banes. Sam and Bumblebee soon have to work together to defeat the decepticons in their return to Earth.