The story starts with Optimus Prime who is regarded as the leader of the Autobots that commissioned of the Transformers' globe destruction, Cybertron. This world is destroyed by Megatron in order to get the whole Spark. The Autobots has the desire to find the Spark. Thus, they have the ability to use it to rebuild Cybertron then finish the war between the Autobots and the Decepticons. Megatron seems to manage in order to locate the Spark on Earth. After tumbling being frozen, Captain Archibald activated Megatron's navigational system as well as his eye glasses were imprinted with the coordinates of the All Spark's location, an incident that left him blind and mentally unstable.
Sam and Autobot Scout Bumblebee Purchase:
Meanwhile, Sam purchases the Autobot Scout Bumblebee on Earth and makes it undercover as a nineteen seventy six Chevrolet Camaroas in order to use it as his car. Moreover, he leaves his house at night in order to send a signal to the rest of Autobots after Bumblebee assisted him in impressing and making a relationship with the girl he loves Mikaela Banes. Later, Sam continues to use Bumblebee as his car and starts to think that someone is going to steal it but he becomes really surprised and shocked when he discovers that his car is a massive and enormous robot.
Sam Is Imprisoned in Jail:
Then, Sam after a certain event is in jail and he tries and does all his effort to convince the officer in the police station about what occurred but the officer ignores his talk and says that he is just an addict on drugs.
The next day Sam leaves his house after Bumblebee returns because he thinks that his car is following him. While he is out, Barricade attacks him and asks him about the glasses of his grandfather. Moreover, Bumblebee which is actually his car rescues him and his girlfriend too.
Mikaela Cuts Frenzy's Head:
At the same time, Mikaela cuts Frenzy's head off but he manages to morph into her cellphone and hide in her purse. In addition, all of them leave to an appointment with the rest of the Autobots who have landed on Earth and transformed into cars too. On the other hand, Sam, Mikaela, and the Autobots go back to home of Sam in order to get the glasses. Nonetheless, agents from Sector 7 arrive and guard Sam and Mikaela. Then, the Autobots interfere in the issue, but Sector 7 captures Bumblebee, keeps him and sends Sam and Mikaela away.
Taking Sam and Mikaela to Hoover Dam:
Moreover, according to the orders of Defense Secretary John Keller, Sam and Mikaela are taken to Hoover Dam undercover as Lennox and Epps. In addition, Frenzy warns the other Decepticons and gets into the computer system. Besides, he frees Megatron from his frozen state. Sam persuades the Sector 7 agents to set Bumblebee free so that he would be able to make the All Spark arrive to Optimus Prime.
Losses of Frenzy's Virus to Government:
Communications of the government were shut down because of Frenzy's virus. However, Keller and two hackers, Maggie and Glen, are able to create a signal to the Air Force to support and encourage the convoy of Autobot-human which has gone to nearby Mission City to hide the All Spark. In fact, during the battle that happens later, The Decepticons attack; Bonecrusher, Frenzy, Jazz, Devastator and Blackout are all dead. Sam was taught to put the All Spark into Optimus Prime's chest but rather than that, he chooses to ram the All Spark cube into Megatron's chest.
End of the Story:
After The All Spark crumble and its power leads to the death of MegMegatron. Optimus takes a fragment of the All Spark from the body of Megatron, but confirms that by destroying it, they won’t be able to get their home world Cybertron back. Later, the government gives orders to close Sector 7 and to dump and put the dead Decepticons into the Laurentian Abyss. Lennox and Epps are getting back with their families, and Sam and Mikaela start a romantic relationship. Finally, Optimus sends a message to all the rest of surviving Autobots in space, informing them that they have now a new home on Earth.