A time of KREO peace

The Autobots settled into their new home on Earth, living on an army base and living with humans.
Sentinel Prime had gone back into space, leaving Optimus to lead his Autobots.
IRONHIDE, another Autobot warrior, had arrived, along with Autobot Wrecker/scientist WHEELJACK. Bumblebee asked Optimus to upgrade him to a warrior, and Prime had started the process of doing this.

Suddenly, the Decepticons were back. Another Autobot warrior who had come to Earth, CLIFFJUMPER, discovered some VEHICONS, the most base form of Decepticon, ripping up ground. They had found a clear purple piece of KREON technology. Cliffjumper reported back to Optimus, who had ominous dreams about a large-scale Decepticon causing destruction in cities. Sentinel appeared to Optimus in a dream, telling him to transform. Optimus woke up reformatted into a new body.

The battle escalated, skirmishes occurring between the two forces. Eventually, the large robot Devastator was rampaging through the cities, drawing out the Autobots for a final confrontation.
By this time, the Decepticons thought destroyed in Space Jail had been found, their deaths a cruel hoax on Megatron. Sentinel came back to Earth, and the battle was intense.

In the end, the Autobots stood triumphant again. This time, the Decepticons and their vehicles were taken to an Earth holding facility to make sure they could not threaten man and KREON kind again.