Superman travels back in time to Krypton prior to its' destruction. Superman saves Krypton from doom, but doing so creates an alternate timeline in which Superman never came to earth and thus the Legion of Doom killed every member of the Superfriends except Robin.
An alien race called the Arslycans use their starship to dump Kryptonite into a black hole. Superman in his Supermobile and Wonder Woman in her Invisible jet are both helping in their noble endeavors. The mission proves to be a very dangerous one though, due to the extremely powerful gravity that the black hole has. Because of the strong gravity, as Superman had feared, the entire Supermobile is pulled into the black hole!
The Supermobile emerges on the other side of the black hole. While he's there, he realizes that he is in the Rao solar system, and both Rao and the planet Krypton are still there. Because of this, Superman realizes that he has emerged from a strange space/time warp, which caused him to travel back in time to a point before Krypton was destroyed.
In a solar system with a red sun, Superman is now powerless. He pilots his Supermobile to the planet Krypton and lands in Argo City. He is greeted by a man and his wife, who welcome him to Krypton. He tells them he is from Earth, a fact that the woman found odd, because she thought he looked more like a man of Krypton than an Earth man. Superman asks what the date is, and the man Zor-El tells him that the year is 5752.8. After hearing the date, Superman realizes that there isn't much time, and he tells them that there's only one more hour before Krypton explodes. At that, Zor-El and his wife Alura rush off. Superman likewise rushes off, heading to Kryptonopolis.
Meanwhile, in the city of Kryptonopolis, in the Hall of Wisdom, Jor-El is begging the Kryptonian High Council to listen to him. He is aware that Krypton's red sun is about to go supernova and destroy Krypton. But the Council laughs at him, telling him he's gone mad. But just then, Superman enters the room and tells them that Jor-El speaks the truth. But still the Council refuse to listen. Jor-El thanks him for trying to appeal to the Council, ultimately realizing it was still only futile. Jor-El tells Superman that he feels like he had met him before and asks who he is, and Superman only says he comes from another time and place.
Superman gets in his Supermobile and quickly pilots it into the center of the red sun known to the Kryptonians as Rao. The star continues to expand as it goes supernova, and Superman ejects some anti-matter into the star, which causes it to reform...shrinking it back down to the size of a normal red giant.
Meanwhile, back on the surface of Krypton, Jor-El and Lara rejoice that Krypton has been saved. Superman tells them goodbye, and he travels back through the space/time warp that brought him there, and he emerges back in the present. He then heads back to earth, arriving at the Hall of Justice in Metropolis. But he realizes that something terrible has happened. Metropolis looks terrible and the Hall of Justice was partially destroyed, and barely standing. As he enters the Hall, the front door falls off the hinges, and he sees that the place has been torn apart, observing debris and rubble all over the place. Emerging from the rubble is Robin, The Boy Wonder. He begs Superman not to hurt him, swearing that he'll surrender without any trouble. Superman asks him what had happened to the place and where all the other Superfriends were. Robin tells him that the Legion of Doom took over earth and enslaved the population. They killed every member of the Superfriends except him. Robin is clearly terrified, telling Superman, "You're not a Superfriend!" It's just then that Superman realizes what had happened. Since he saved Krypton in the past, the timeline had been altered. As a baby, Kal-El was never sent to Earth, so in this new reality, there never was a Superman on Earth. And because of that the Legion of Doom easily took over the world and destroyed the Superfriends. Superman tells Robin that he'll set the timeline back to the way it was. And Robin just looks at him as if wondering what in the world he's talking about, likely thinking he's crazy.
Superman gets in his Supermobile and returns to the black hole that sent him back in time before, and he returns to Rao and removes the anti-matter. He then returns to Krypton to watch baby Kal-El blast off into space. He runs back to the Supermobile, seeing that the expanding star is continuing to supernova, and he blasts off just as Krypton explodes. Superman is saddened by his loss, but he realizes that in order for Earth to live without the reign of the Legion of Doom, Krypton must die.
Superman then returns to the space/time warp and arrives in the present seeing things are just as he left them before the timeline was changed. Wonder Woman and the Arslycans were worried that he had been killed, but he had only been gone for a short time. But Superman tells them that it may have been moments to them, but it was a lifetime to him. The Arslycans head back home, and the Invisible jet and Supermobile head back to earth.
|V o i c e A c t o r||R o l e|
|Shannon Farnon||Wonder Woman|
|G u e s t C a s t|
|???||Science Council member|
- Rao solar system
- During the scene within the alternate timeline, the tone is pretty serious for an episode of the Superfriends, due to the grim setting and Robin's almost disturbing fearful reaction to Superman.
- This episode is one of the few episodes that Robin appears in without Batman present.
- This episode is also one of the few episodes with Robin in which he doesn't say "Holy this or Holy that...", a popular catchphrase of his.
- Although never explicitly stated, it is strongly implied that because Superman traveled back in time and warned his uncle and aunt, Zor-El and Alura, that Krypton was doomed, that is why they were able to save Argo City, which allowed Supergirl to be born years later. That would mean it's a predestination paradox.
"Syndrome" in the title refers to the "sickness" that the universe took on after Krypton was saved via time travel. Despite the fact that Krypton survived, Earth did not, at least not in the way it was supposed to, since the world was practically destroyed and under the rule of the Legion of Doom, therefore one could say that earth was suffering from the "Krypton Syndrome."
- ↑ Although aired on this date in some countries, this episode was not aired in the U.S. until 1995, as part of The Superman/Batman Adventures, although in an edited form. (We need the exact airdate)
- ↑ The Legion of Doom were referenced only, not seen.
- ↑ The name of the city wasn't given, but it's strongly implied that it's supposed to be Argo City, based on the fact that it's almost certain that the Kryptonian couple he talked to was Zor-El and Alura.
- ↑ Apparently, according to the comic books, Kryptonian eyes are colored distinctively different than most human eyes. This may have been how Alura recognized he looked more Kryptonian than human.
- ↑ Apparently to prepare to save Argo City, as it was the case in the comics. (Argo City is protected by a large dome and blown out into space unharmed by the destruction of Krypton)