Transformers - Autobot
The Autobot storyline begins with one of the Autobots, Bumblebee, landing on Earth. Bumblebee scans a second-generation Chevrolet Camaro as his alternate mode. After receiving a transmission from Optimus Prime, the Autobot leader, things start going wrong when Bumblebee encounters several Decepticon drones. After defeating the drones, Optimus explains to Bumblebee that a human named Sam Witwicky is in possession of an artifact which can reveal the location of the Allspark, and it is Bumblebee's mission to find Sam. Sam then buys Bumblebee as his new car after another Camaro blew its tyre somehow at the car lot.
Later, Sam and his girlfriend, Mikaela Banes, are attacked by one of the Decepticons, Barricade, but Bumblebee saves them. Bumblebee fights Barricade, while Sam and Mikaela escape. After defeating the Decepticon, Bumblebee finds Sam and Mikaela, who thank him for saving them. Optimus contacts Bumblebee, telling him that Sam has the artifact that contains the location of the All Spark, and Bumblebee must protect Sam at all costs.
All Autobots, Optimus, Ironhide, Ratchet, and Jazz land on Earth, assume alternate forms (a Peterbilt 379, a GMC Topkick, a Pontiac Solstice and a Hummer H2 Search and Rescue vehicle) and meet with Bumblebee, Sam and Mikaela. Sam gives them the artifact, which turns out to be his grandfather's glasses, to Optimus, who explains to Sam and Mikaela the mission of the Autobots in Earth: they are in the search of the All Spark, a powerful artifact which is the source of life of all Transformers, so they can use it to revitalize Cybertron, the homeworld of the Transformers. Ratchet reveals Sam's grandfather discovered their enemy, the Decepticon leader Megatron, trapped in the Arctic. Megatron burned the information of the All Spark's location in Sam's grandfather's glasses so the Decepticons could find the All Spark. Afterwards, Mikaela sarcastically states that she is struggling with why Bumblebee disguised himself as such a "beater", and in response, Bumblebee scans a new and improved Camaro as his new alt-mode.
Ironhide detects Sector 7 helicopters and Prime orders Jazz to create a diversion so that the Autobots, Sam and Mikaela can escape. In doing so, Jazz is cornered by Sector 7 agents. Ironhide rescues Jazz from Sector 7, and manages to defeat several drones on the way (it is revealed here that Ironhide was partially responsible for the destruction of the Cybertron moon Cyber 5). After defeating the drones, Ironhide discovers that Sector 7 is trying to capture Bumblebee. Prime tries to rescue Bumblebee but he fails to save his comrade as he is taken away by Sector 7, partially because of Shockwave. Optimus defeats Shockwave and decodes his transmissions, discovering Starscream, Megatron's second-in-command, also knows of the All Spark-and Megatron's-whereabouts. With their mission clear, the Autobots decide to rescue Bumblebee, Sam and Mikaela from Sector 7. Bumblebee, Sam and Mikaela are captured inside Hoover Dam.
A power outage allows Bumblebee to escape. While exploring Bumblebee finds the frozen Megatron and the All Spark. Bumblebee recovers the All Spark and rescues Sam and Mikaela, and then flee when Megatron awakens. Starscream and another Decepticon, Blackout, fly through the dam and cause several explosions which allow Megatron to escape.
Bumblebee, Sam and Mikaela travel to Mission City with the All Spark. The All Spark's power surges transform human machines into feral drones, which attack Bumblebee. However, Ironhide rescues Bumblebee and defeats the drones. Meanwhile, Jazz encounters and fights Starscream and Blackout. Jazz manages to defeat the Decepticon duo, but another Decepticon---Brawl---appears behind him and kills him, in front of Ironhide. The Autobot then defeats Brawl in a "slow death", avenging his fallen comrade. Bumblebee, however, fights Barricade, who is trying to take the All Spark.
Bumblebee defeats the Decepticon and meets with Sam and Mikaela but Megatron appears behind him and quickly defeats Bumblebee, forcing Sam and Mikaela to run away. Megatron is about to kill Sam and Mikaela, but Optimus knocks Megatron aside, challenging him to a final battle.
Optimus defeats Megatron, however, just as Sam is about to give Optimus the All Spark, Megatron jumps up and tries to kill Prime in one last attempt using his flail. However, Optimus catches Megatron's flail and pulls him in closer while crushing the All Spark in his other hand, and plunging it straight into Megatron's chest, presumably uniting with his Spark, killing him instantly. The story ends with Optimus and the Autobots choosing to remain on Earth.
Transformers - Autobot