Jimmy, Carl, and Sheen are kicking back and watching wrestling when Brobot, Jimmy's robotic little brother from the previous episode "Brobot," appears on screen. He tells them that he and his robot parents are being attacked by "Moonie-Men" and begs Jimmy to come and help. Carl summarizes their previous adventures with Brobot and Jimmy ignores the message. Sheen and Carl insist that he needs to go save his brother and Jimmy is persuaded to help, as long as the two of them come with him. At first Sheen and Carl refuse, but they change their minds once Jimmy tells them there will be no TV until they agree to leave. On the way to the moon, Sheen asks several questions regarding how Jimmy and his friends constantly defy the laws of physics, but the answers are drowned out by a happily singing Carl. Sheen and Carl also try to convince Jimmy to let them stay in the rocket, but he refuses.
Once on the moon, the three spot a strange figure approaching in the distance. They are extremely scared and hide behind rocks as the figure comes towards them. It turns out that it is only Brobot. An annoyed Jimmy asks where the Moonie Men are, but it turns out Brobot only made them up because he wanted to play with Jimmy. Sheen tells Brobot the story of "The Boy Who Cried Wolf" in order to teach him a lesson, but Brobot doesn't get it. Jimmy insists that they are going home and starts to walk back to the rocket. Brobot acts sad and wins Jimmy over.
Jimmy, Carl, and Sheen collect crystals on the moon as Jimmy complains about Brobot. Suddenly, a dark space cloud appears. Brobot is terrified and says that this is the horrible scary Junkman, who took his parents. Jimmy drags Carl and Sheen off the moon, saying that Brobot should stay and tell his stories to himself. On the way home, they happily talk about how they can still catch the last few minutes of wrestling. Suddenly, the space cloud appears again and an eerie green light sucks the rocket into it.
It turns out that the Junkman was real and they are stuck on his space ship. He introduces himself to the boys while playing dramatic piano music. He scans Jimmy, Sheen, and Carl and declares them to be relatively worthless. He is however, impressed by the rocket, saying he can use it to make toilets. The Junkman's dog, Roxie, enters and Godard is smitten by her. He tries to flirt with her, but the Junkman notices and imprisons the robot dog and the boys.
On the way to the cell, Jimmy, Sheen, and Carl see Brobot's parents, who are quite friendly and unconcerned about their fate. Once inside their prison, Sheen plays the harmonica and Jimmy apologizes for not believing Brobot. At this moment, Brobot appears – he hid on the bottom of Jimmy's rocket and is here to bust the boys out! He asks them if they are now going to help him save his parents, Sheen and Carl really do not want to, but Jimmy agrees. They sneak about the spaceship as Jimmy tells everyone the plan – they are to save Brobot's parents and Goddard, find the spaceship, and leave.
The scene switches to the Junkman trying to figure out what to sell Goddard for. He receives a call from Gortox the Irritable, who is wondering where the Gravadiscs the Junkman promised him are. The Junkman is planning to use Brobot's parents for the toys, and he puts them on a conveyer belt, asking them if they have any last words. Jimmy, Sheen, Carl, and Brobot come to the scene. They try to think of what to do and finally agree that Brobot should distract the Junkman – something he is quite adept at. While the Junkman chases after Brobot, Sheen and Carl grab Brobot's parents off the conveyer belt and make a run for the rocket.
Meanwhile, Goddard has finally won over Roxie's heart. The Junkman is greatly angered by this and the fact that Jimmy, Sheen, and Carl has escaped. He tells Roxie to get them, but she turns on him, allowing Brobot's parents to tie him up. The Junkman attempts to attack them while tied to a rolling chair and ends up knocking off the steering wheel of his ship, which careens into space. The Junkman insists that he is the only one who can save them and Jimmy unties him under the condition that he will just save them and leave. He breaks his promise and runs into an escape pod with Roxie. Jimmy tries to get the ship under control; Brobot insists that he can help and manages to save them.
Everyone enjoys a snack of moon pies on the moon while Brobot and Jimmy play Moon-Tennis together.