The Legion work to repair the damaged cruiser and Bouncing Boy decides they need to get help. The Legion break into Takron-Galtos, a prison planet, and prepare to release… the Fatal Five.
The Legionnaires get to the cells and the Fatal Five agrees, but needs the Emerald Eye and the Persuader's Axe. Once they recover their weapons and escape, Bouncing Boy and Brainiac 5 explain that they've created a solar transducer and the various teams must acquire the necessary part. They send Superman to find the Controller using the Sun-Eater, but he's unaware they're sending him away so that he'll be safe and can return to the past, keeping time on track. Superman manages to spot the Controller with infrared vision and approaches, but the Controller is aware he's coming.
The Legion and Fatal finish the device just as the Sun-Eater enters the Solar System. Meanwhile, a door on the Controller's ship opens for Superman and he enters. The Controller says the United Federation doesn't suit his desire for chaos, and Superman attacks him only to hit an impenetrable force field. The Controller then dons a battle suit, making him a match for Superman.
The Legion, Fatal Five, and Substitutes all join forces and the Emerald Empress slows down the Sun-Eater and attack the Controller's robots. The Persuader and Tharok get through the force field to reach the Sun-Eater's core so Matter-Eater Lad can eat it open and Tharok can destroy it. Meanwhile, Superman attacks the Controller's ship directly. Tharok drops the core's force field and Brainiac 5 operates the transducer and Timber Wolf gets the team at the core out just in time. Brainiac 5 fires the transducer into the Sun-Eater. Aboard the cruiser, Saturn Girl realizes that the Emerald Empress has imprisoned all of the heroes now that the weapon is out of the way, and plans to leave the team there when the supernova goes off. However, Bouncing Boy anticipated their double-cross and had Shrinking Violet sabotage their efforts. They get clear but the transducer fails to operate.
The Sun-Eater continues on course for Sol while the Controller holds off Superman. Brainiac 5 realizes a critical component was destroyed when it hit the core and they have only minuets to take in a replacement. Ferro Lad, aware of what needs to be done, turns into his metallic form and flies into the core to make up for failing earlier. He destroys the first wave of the Controller's robots but the second wave encircle him and try to blast him down. He throws them off and climbs into the transducer, says, "Long live the Legion," and uses his body as a conduct to trigger the device. The Legion look on as the Sun-Eater is destroyed.
The Controller taunts Superman with the death of his friend and the Man of Steel rips apart his suit then blasts apart his controls. The Controller leaves through a teleport gate but Superman warns that if he returns he'll finish him for good.
Later at Legion HQ, Superman delivers the eulogy for their fallen comrade, unaware that Ferro Lad's body is lying on an asteroid.
Later Superman prepares to go back to his own time and everyone has a group hug. He departs in the time sphere and arrives back in Smallville at the moment he left, where he was preparing to leave for Metropolis. He goes down for dinner, leaving his Legion Ring… for now.
Shrinking Violet first appeared in Action Comics #276 (May 1961) and was created by Jerry Siegel and Jim Mooney. Salu Digby comes from the planet Imsk, where all of the inhabitants have the ability to shrink to an unspecified size, potentially to the atomic or subatomic level. Typically Shrinking Violet operates at a size of approximately 6". Shrinking Violet is also a skilled hand-to-hand fighter, having overcome her initial shyness. Post-Zero Hour she was rebooted as Shrinking Violet, but later gained the power to grow to giant-size as well as shrink and used the names LeViathan and then Violet. In the most recent continuity as of this episode's initial airing, she is now known as Atom Girl and her membership in the Legion is kept a secret to most members and the public at large.