Sixty-five million years ago, alien beings began wiping out most life on Earth. Somewhere in the Arctic, a geologist named Darcy Tirrell discovers dinosaur corpses covered in a strange metal. Five years later after the battle of Chicago, one of their government is supposed to hunt down remaining Decepticons, but they are keeping a secret that are really hunting down Autobots. They are supported by a bounty hunter named Lockdown and he is killing Ratchet because his primary target is Optimus Prime and he wants him alive. In Texas, Cade and his friend Lucas just bought the old truck and leasing a home. So Cade decide to look at the old truck by taking it apart and he told his daughter and his friend that he found Optimus; then Cade and his friend starting reviving him. It causes Cemetery Wind and Lockdown to attack and threaten the Yeagers before Optimus attacks. Cade, Tessa and Lucas were saved by Tessa's secret boyfriend, Shane Dyson. After a long chase through the town, one of Lockdown's grenades kills Lucas while the others escape and Optimus is going to reunite with other Autobots. After everyone was reunited, Cade used the drone from their enemy and showed the video of what happened to other Autobots and Optimus. The Autobots, and their new friends were going to find out who is behind the plan and going to know what is going on by going to KSI in Chicago. Joshua Joyce head of KSI showed Darcy that he perfected Transfermium, the metal that the Transformers were composed of but he needs more. Also he has imprisoned Brains to decode dead Transformers and utilize their data for human-created Transformers. Joshua showed Darcy his prized creation of Galvatron he created by using data from Megatron. The Autobots storm the facility, but Joshua stops them. But they don't need the Autobots now because they can create their own Transformers and want the Autobots leave. Joshua send Galvatron and Slinger attack the Autobots. When Lockdown showed up he captured him and Tessa to send them on Lockdown’s ship and also Lockdown explained to Optimus that their creator wanted him back. Lockdown gave the Seed to Cemetery Wind for a trade. After Optimus was rescued and escaped, Optimus told Cade, Tessa and her boyfriend that he since Megatron. So Brain told the Galatron that Megatron was reborn and manipulated KSI in order to steal the Seed and create more Decepticons to wipe out humanity and extinction for ever. Cade warns Joshua about Galvatron's plan. Then there was an outbreak and the Autobots needed to get that Seed out of the city. After the Autobots got the Seed to safety, Optimus and his new friends face Lockdown and kill him. When it was over Optimus believed that he has a bounty on his head, which causes him to leave Earth alone. Galvatron is still alive but Optimus doesn’t know if he will come back to Earth or not.