Three superheroes from the future travel to the past and join Clark in hopes that together they can defeat Brainiac, who has taken over Chloe's body.

Clark is attacked by the Persuader in his barn, but before he is killed a trio of superpowered aliens, called the Legion, shows up and saves him. While inhabiting Chloe's body, Brainiac informs Davis that he will soon become the creature "Doomsday" permanently, and places him in an ice cocoon for the metamorphosis. Rokk, Imra, and Garth inform Clark that today was the day he was supposed to destroy Brainiac for good, but because the only way for him to do that will be to kill Chloe. Brainiac begins sucking the knowledge from every human mind through the world's computer network when he is attacked by the Legion. Before the Legion can kill Chloe Clark intervenes and convinces them to focus their powers and pull Brainiac out of Chloe. Afterward, the Legion takes what is left of Brainiac with them back to the future to reprogram him for something positive.