“Save the Roboter Farm!” (Or “Rainbow Canyon” in the English Dub) is the 5th episode in the 2003 Astro Boy series (Although it is the 7th episode in the DVD box release.).

The episode begins with a girl named Mimi running into the Ministry of Science searching for Astro Boy when she is stopped by two guards, asking her what she needs, and telling her that she couldn't simply expect Astro to come and help when suddenly Astro comes up and asks her what the problem is. She begins to speak of storms and earthquakes that are ravaging her grandfather's farm. When asked why her grandfather couldn't come, she replies that he is stuck under a tomato, making the guards laugh, much to her dismay. When Astro offers her his help, she grabs his arm, and runs off from the Ministry of Science, taking Astro with her, and tells him she does not want people laughing at her grandfather. When Astro tells her that he knows those people and that they wouldn't laugh, Mimi responds by telling him that sometimes “They can turn their back on you.” and proceeds to ask if he can fly, to which Astro responds yes. The episode cuts to Dr. O'Shay explaining to Yuko what Rainbow Canyon is. Rainbow Canyon is a former dried up canyon converted into a farm by Dr. Geronimi using advanced technology (A giant tower that produces rays) that can create rain clouds in order to fertilize the soil, however, Dr. O'Shay is puzzled as to why Mimi would need Astro's help. The scene cuts to Mimi explaining how she and her grandfather (Dr. Geronimo) came to Rainbow Canyon and converted it into a farm with the Environmental Control tower, and created Vegibots (Or Veggiebots) to help harvest the vegetables. They soon arrive to Rainbow Canyon, but to Astro's dismay, he almost crashes into a giant tomato. Mimi explains that they're a part of her grandfather's experiment (And that 1 tomato is enough to make 100 bottles of ketchup). She also points out a Vegibot, but the moment is cut short as an earthquake starts. Dr. Geronimo appears and tells Mimi to take cover, but he is almost hit by a giant grape. Astro proceeds to pick Mimi and her grandfather up, and flies to the safety of their home (Whilst dodging a variety of giant vegetables, including Pod Peas, Corn, and a Bell Pepper.). Upon arriving to safety, the earthquake has stopped, but the damage has already been done, and Astro remarks that he is afraid that their vegetable farm looks like “A tossed salad.”. Mimi responds that it's because she trusted someone she considered a friend. She proceeds to run to her room exclaiming that she will never trust anyone again, leaving Astro to ask Dr. Geronimo what Mimi was talking about. Dr. Geronimo proceeds to tell Astro that approximately one week before the events taking place, a man named Katari came to the farm looking for work. He was “Smart and cheerful, and a big help around the farm.”, causing Mimi to get bond with him. She then took him to the Environmental Control tower, but he kicked her out, and had been causing the earthquakes ever since. Soon, a storm starts much to their surprise, leading Astro to tell Dr. Geronimo that they must leave immediately, however, when Astro tries to go and get Mimi, she is not in her room. The scene cuts to Mimi sneaking into the tower by climbing through a hole caused by all the damage. Astro soon breaks in through the glass roof, and finds Mimi. Katari views all of this through a monitor, and leaves the control room, telling them he no longer has any control over the system and needs their help. Mimi points out that he was causing the problems in the first place, to which Katari says that he was only trying to fix a flaw he found in the system, and had to act quickly. He also points out that he'd have nothing to gain from destroying the farm, convincing Astro he should help him. The scene cuts to Dr. O'Shay realizing a dam has burst, meaning the farm will be completely obliterated. The scene cuts back to Katari, Mimi, and Astro. Katari opens a hatch, telling them there is no time, but proceeds to push them down a flight of stairs, knocking Mimi out. Katari proceeds to close it, and tells Astro that the hatch will explode if he tries to open it. Katari then proceeds to tell Astro his plan: He will make it look like the Vegibots rebelled, and destroyed both Mimi and Dr. Geronimo, as well as the farm, and that not even Astro could have stopped it. He proceeds to leave via jetpack, and leaves them to die. Mimi awakens and points out that Katari “Is a horrible man”, and proceeds to tell Astro that he will never know what it's like to have his heart broken because he's a robot. However, the moment is cut short as the building crumbles around them, and Astro picks up Mimi, proceeding to escape the Environmental Control Tower. The scene cuts back to Dr. O'Shay, telling Yuko to advise everyone in Rainbow Canyon to evacuate due to the flood. It then shows Dr. Geronimo trying to evacuate the Vegibots, however, they will not leave because they do not want to leave the farm. Astro solves this by teaming up with the Vegibots. While he makes a new canal, the Vegibots create a barrier from the giant vegetables, and this proves effective. Meanwhile, Katari is telling the news that the Vegibots revolted, and killed Mimi and Astro. However, Mimi shows up and proves him wrong. While Katari is being arrested, it is found out that he is actually part of an Anti-Robot group. The episode ends with Astro and Mimi flying through a rainbow.