Janitor Rudy Jones runs into an accident with nuclear waste and becomes Parasite. He feeds on the energy of others, with his number one choice being Superman. In doing so, he discovers Superman's identity.

Brainiac, once Krypton's all-knowing planetary computer, comes to Earth as part of his information-gathering trek across the galaxy, and partners with Lex Luthor on the basis of giving technological progress to humanity. But, as Superman discovers, Brainiac's intent after gathering the world's knowledge is to destroy Earth.