Dr. Hämsterviel sends Experiment 010 back to Gantu because he has been driving him crazy. Gantu is not happy to have 010 back, and throws him out soon after being teleported. Meanwhile, Stitch is playing video games when he notices Lilo has boarded up the windows. It is time for his bath, and Lilo has sealed off any chance of escape. Lilo chases Stitch around the house with a soap and brush, making a lot of mess behind them. Nani arrives home to pack for an overnight trip, and while she is away asks Lilo and Stitch to keep the house tidy. Pleakley intends to make sure they do, but soon after Nani leaves Lilo and Stitch run off to the beach, celebrating their newfound freedom. However, they find that Cannonball has been causing a lot of waves that have caused rubbish to wash up on the beach. They get him to stop and as they start cleaning up the mess 010 shows up and does the job for them. They capture him in a picnic basket, just as Moses arrives up to clean the beach. He is amazed by how tidy the beach is and assumes that it was Lilo who did it. He offers her and Stitch to help with the spring cleaning at the hula school, but they decline.
Lilo and Stitch return home with 010, who Lilo has named Felix since all neat freaks on TV are called that. According to Jumba, 010 is designed to be a total neat freak and keep everything spick-and-span. Equipped with tiny brushes and hormonal detergents, he has thee functions: automatically tidy up all messes, digest process all garbage and trash, and antisceptisize against all unhealthy germs and sources of filth. Lilo thinks Felix would make a good friend for Pleakley, but objects mainly because he is one of Jumba's evil experiments. Lilo is certain that Felix is not dangerous, but still asks Jumba if it is true. Jumba recalls a certain flaw with 010, but is certain he fixed that problem long ago. However, soon after everyone leaves the room, Felix spots a fly and sterilizes it with lasers from his nose, indicating that he may be dangerous after all.
After agreeing they already have one neat freak at home, Lilo and Stitch bring Felix to the hula school to help with the spring cleaning, thinking he could work as the janitor. Felix immediately starts cleaning the auditorium, and so far it all goes well until he tries to digest Moses' oriental rug. Lilo tries to stop him, but the two end up tearing it. Lilo takes the blame, and Moses kindly asks her to go home. Pretty soon, Lilo and Stitch are no longer impressed with Felix. His obsessive cleanliness starts to get annoying, but Pleakley starts to like him when he sees how useful he is around the house. However, his tone changes when Felix throws out his antique sewing machine. To make matters worse, Felix traps Lilo, Stitch, and Jumba in the house. It is at this point that Jumba remembers he did not fix the flaw in 010's programming. The flaw was that Felix viewed all organisms (including people) as germs that must be sterilized at all cost. This means he sees Lilo, Stitch, and Jumba as germs to antisceptisize.
Felix relentlessly pursues Lilo, Stitch and Jumba around the house, shooting lasers at them. Eventually, they capture Felix in a container and Jumba starts work on reprogramming him to be less of a neat freak. After a while, Jumba presents Felix to Lilo, Stitch, and Pleakley, no longer obsessively neat. Lilo tests him out by making a mess. As expected, Felix does not react, not even if she makes the mess worse. Just then, Felix approaches the mess, but instead of cleaning it up he makes a much bigger mess throughout the house when he gives a big blow through his nose. It turns out that instead of just liking dirt, Jumba's reprogramming has caused Felix to begin making things incredibly dirty. Now he was more of an Oscar than a Felix. To make matters worse, Nani calls saying she is coming home early. Since there is no time to reprogram Felix again, and Pleakley refuses to clean for Lilo, she and Stitch reluctantly go around the house cleaning up the mess themselves. They finish giving each other a bath just as Nani walks through the door, very impressed with how tidy the house is.
As for Felix, Lilo and Stitch give him back to Gantu. He is at first delighted to see Felix until he realizes too late that is no longer a neat freak when starts to mess up his recently tidy ship.
- Moral: It's good to be clean, but not obsessively clean.
- Jumba revealed that he doesn't bathe himself, although it is unknown if he cares little about his personal hygiene or has even bathed in his life.
- When Jumba claims to have fixed Felix's glitch and that he wouldn't hurt a housefly, Felix can be seen obliterating an actual housefly, which contradicts Jumba's claim.
- Moses revealed that the oriental rug, which Felix attempted to destroy, was over a hundred years old and made by Queen Liliuokalani herself, the last Hawaiian monarch whom Lilo and Nani's names possibly come from.
- In this episode, Cannonball was seen ruining the beach with his tsunami-sized waves, implying that he was still incompletely rehabilitated.
- At one point, Gantu complains about the garbage on his ship and hints that he probably should have kicked out Reuben instead of Felix, to which Reuben sarcastically agrees.