For a few days, unidentified flying objects are appearing over the sky of Metropolis. They flash from one side of the sky to the other in groups, and then suddenly disappear.
One such day, Lois and Clark are walking down the street, when suddenly the ufos appear in the sky. Clark investigates them with his x-ray vision, but fails to detect their working due to their protective forcefield. They go to the Daily Planet building, where they are met by Lana Lang, Clark’s best friend from Smallville. She informs him that Morgan wants to see him.
Morgan informs Clark that he wants to send him on a mandatory vacation. Clark is upset, but Jimmy is elated at the news. He suggests that Kent should go on a vacation. But, suddenly he loses consciousness. Minutes later at the hospital, he is diagnosed with flu. Jimmy gives his Clark ultrasonic watch and advises him to call on Superman when the need arises. Clark obeys and takes the watch.
Sometime later, Superman is finished patrolling the city and is returning to change back to Clark Kent. Unbeknownst to him, a strange flying object follows him and disappears out of sight. Superman is changing his dress, when he hears an unearthly sound coming from Corliss apartment. He goes up to investigate and saves Lyle Corliss from the mysterious object, destroying it in the process. He collects the fragments and goes away with them.
Later when Clark comes to visit Corliss, he is greeted by an alien humanoid, who had taken the form of Corliss. He incinerates Clark’s coat and reveals Superman, then traps him in a dimensional projector. Then he adds that the ufos the people are seeing, are actually Yota Transmissions to an alien fleet, which is preparing an attack on Earth.
The dimensional field inside the projector has a tranquilizing effect on Superman. Yet somehow he manages to activate Jimmy’s signal watch. He concentrates on the frequency and breaks free of the projector. Corliss tells him that he is too late to save earth. The last Yota transmissions have already been sent. Superman chases the transmissions, and accelerates into hyperspace. He alters them with his x-ray vision, then disappears from the scene.
A few million miles later, a waiting alien fleet receives the transmissions and reads it as an abort signal. The commander is disappointed but tells that he shall keep watch on earth.
The next day, reports of Corliss’ arrest is seen on the newspaper. Jimmy is recovering and Perry welcomes Clark back to work.