In the Transformers: Crossfire storyline, Optimus Prime and the Autobots must protect a human boy named Zach, who is revealed to be the key to the Allspark, a powerful cybertronian artifact on Earth. The Decepticons learn of Zach's importance and launch a full-scale invasion to capture him and use him to unlock the Allspark's power for their own destructive purposes. The Autobots and the humans must band together to defend Earth and prevent the Decepticons from obtaining the ultimate weapon.