While searching for reusable equipment at the junkyard, the Turtles witness a spaceship crash-landing on Earth. After debating whether the occupant is hostile or not, the Turtles venture inside. Its only occupant: a small funny-looking alien child, named Quarx.
Another spaceship lands nearby, and a brutish-looking alien named Drako declares that he's located "the starchild." He attacks when Quarx is playing with the garbage, and the Turtles immediately fight back. Drako declares that "the starchild" is the most dangerous being in the universe, and flees back to his own ship.
The Turtles bring Quarx back to the lair, where he exhibits telekinetic abilities, sending their weapons flying through the room. Splinter also senses immense anger from him. Quarx flies out of the sewer and into the city beyond, and as the Turtles try to track him down, Splinter heads to the ship to learn about him.
The Turtles find Quarx by listening to a police-band transmission, and Michelangelo manages to convince Quarx that if he comes with them, they'll give him "even more awesome toys." As they try to stop him from manipulating cop cars, April tips them off that alien starfighters are flying over the city - Drako has returned with reinforcements.
Leonardo and Michelangelo take on the alien bounty hunters, while Raphael and Donatello try to track down Quarx (who repeatedly declares that he just wants to play, and that he won't obey the Turtles because "you're not my father!"). Drako tells them that unless they capture Quarx, all of Earth could be obliterated. Thousands of ships appear, demanding the starchild's return and threatening to obliterate Earth if they don't get him within half an hour.
Drako reveals that "the starchild" has caused destruction across the galaxy with his powers, and that the aliens trying to catch him have been pursuing him for two centuries. The armada are willing to sacrifice Earth in order to save other worlds.
On the crashed spaceship, Splinter shows Donatello a recording of scientific experiments that gave Quarx his powers, and the terrible results of the experiment. Quarx won't "grow up" for anyone but his father, and his immaturity is threatening the whole planet. To keep him from flying off, the Turtles play around on a playground until he decides to join them... only for Drako to interrupt. Drako reveals that he is one of Quarx's species, and uses a mind-control ray on the child so that Drako can conquer the universe using his powers.
Suddenly Quarx's father appears and tells him that he has to use his powers to create galactic peace, and that he needs to grow up. It turns out that the father was actually Splinter in a disguise.
Quarx transforms into his adult form, and uses his powers to repair everything that had been damaged or destroyed. He offers to undo all the damage he has done on all the alien worlds he's attacked, and the aliens accept his offer. He flies away into space.
As Splinter ponders about growing up and maturing, the Turtles slip off one by one, and Donatello mentions that, "We'll get around to maturing... one of these days."
- Leonardo (Cam Clarke)
- Donatello (Barry Gordon)
- Raphael (Rob Paulsen)
- Michelangelo (Townsend Coleman)
- Splinter (Peter Renaday)
- April O'Neil (Renae Jacobs)
- Vernon Fenwick (Peter Renaday)
- Quarx (Elizabeth Daily)
- Drako (Cam Clarke)
- Marrick (Peter Renaday)
- Adult Quarx (Cam Clarke)
- Tank Driver (Townsend Coleman)
- Turtle Van
- Drako's Ship Fleet
Home media releases
- Teenage Mutant Ninja Turtles: The Starchild
- Teenage Mutant Ninja Turtles Season 7
- Teenage Mutant Ninja Turtles: The Complete Classic Series Collection
In the cartoon Defenders Of The Earth of 1986 was exhibited a similar episode titled The Starboy.
- When Quarx attacks the turtles with their own weapons in the lair, one of the weapons gets stuck in the top of the stop sign hanging on the wall. In the next shot, it is suddenly stuck in the wall slightly above the stop sign.