While enjoying a day off with Firestorm, Cyborg is captured by the robot minions of supercomputer Brainiac, who intends to use the bionic dogooder for one of his typically evil "mind-blowing" experiments. To save the life of his fellow Galactic Guardian, Firestorm enlists the aid of Superman and rushes to Cyborg's rescue. But it may already be too late: The two superpowered good guys are confronted by a gigantic killer robot... with Cyborg's brain and intellect trapped inside its power source!