A foreign object enters Earth's atmosphere above Metropolis, and Superman investigates, finding a drone that engages him in combat. Superman easily defeats it, and takes it to the Fortress of Solitude. Supergirl tells him of Brainiac, a conqueror who once removed the entire city of Kandor from the surface of Krypton. Superman follows the drone's signal into space, finding an alien ship bottling a city. He fights Brainiac on the ship as it closes in on Earth, and Kara and Krypto fight a drone battalion. Brainiac is imprisoned, and Kandor is unbottled on Earth. Brainiac turns out to be another drone as its signal reaches the real Brainiac, who soon enters the atmosphere with his skull ship.
