"No P in the Ool" is the pilot episode of Codename: Kids Next Door. It first aired in 2001 as part of "Cartoon Network's Big Pick," and won a viewer poll to be made into a full series.
The episode starts with the operatives of Sector V each being called by Numbuh 1 to the meeting room of the treehouse. Numbuh 1 explains that adults have extended their swimming hours at the local pool so that kids have no time at all, and that they are going to put a stop to this.
Upon arriving at the pool and realizing that they have no specific plan of action, the KND decide to simply jump into the pool. The lifeguards, Mr. Wink and Mr. Fibb, see them and activate an electric fence which rises around the pool, shocking them.
They tell the children that it is currently adult swim, but they are welcome to play in the "kiddie pool", which turns out to be an extremely small inflatable pool. The rest of Sector V don't seem to mind this much, while Numbuh 1 refuses to put up with it and yells out, for the first time ever, "Kids Next Door, Battle Stations!"
The five members then spring into action, summoning the Kid-a-Pult, and launching Numbuh 2 over the fence, hitting the lifeguard chair and knocking Wink and Fibb into the pool.
The kids are then free to play in the pool, until Mr. Wink and Fibb arise in their lifeguard chair, which turns into a robotic, laser-firing walker. As the super chair looms over the Kids Next Door, Numbuh 1 suggests they go back to the Kid-a-Pult...
...Which is then immediately destroyed by the super chair. Numbuh 1 then notices that Numbuh 3 is missing, and the team tells him that she went to get snacks. Numbuh 3 then returns with snacks just as the chair is about to destroy them, giving snacks to everyone except Numbuh 1, including the villains, who leave their chair to eat ice cream.
Numbuh 1, infuriated, starts yelling at Numbuh 3 for giving treats to the bad guys when he notices that the super chair has been abandoned. He hijacks the chair and tries to get rid of Mr. Wink and Mr. Fibb, but instead accidentally activates a drilling device that drills a hole in the pool and drains it. This angers everyone, and Numbuh 1 then nervously says, "So, who's going to the kiddie pool?"
For most of the episode, the kids are in swimsuits rather than their usual clothes.
Mr. Wink and Mr. Fibb are the first adult villains ever to appear on the show, their second episode being Operation: C.O.W.G.I.R.L..
The art style is noticeably more simplistic than the rest of the series. The outlines are unusually thick.
The KND logo shown during scene transitions is blue rather than yellow. This also applies to Operation: C.A.K.E.D..
Numbuh 4 is shown swimming, while in later episodes it is established that he cannot swim.
The character's voices had not been fully developed when this episode was created, as Numbuh 3's Asian accent is more noticeable than in the rest of the series, as does Numbuh 4's Australian accent. Numbuh 1's voice actor Ben Diskin was 17 or 18 years old when he recorded this episode.
Numbuh 3's love of popcorn appears in this episode (it was the snack she got for herself at the snack bar).
On Numbuh 1's podium in the beginning of the episode, "KND" is painted on it in white paint. However, in the rest of the series, his podium has the number 1 on it instead.
Kenny and Chimpy from Kenny and the Chimp is seen as the KND is running towards the pool, before the fence comes up.
Numbuh 1's sunglasses do not have their usual shine to them in the beginning of this episode.
Numbuh 2 is the only one to be shot out of the Kidapult. They likely shot him because he is the fattest and biggest member of Sector V and would give the enemy the hardest hit.
The characters' necks are abnormally long in this episode; most likely because this was the very first episode of Codename: Kids Next Door.
This is the only episode when a KND Satellite intercepts a phone call.
When Numbuh 2 sent everyone in their pods from the C.O.O.L.B.U.S. you can clearly see Numbuh 5's image in Numbuh 4's pod, while in Numbuh 5's pod, Numbuh 5 is there herself.
Numbuh 4 said, "Let's do it!" in Numbuh 2's voice.
Before Numbuh 1 accidentally drains the pool, Numbuhs 2-5 are seen in their swimsuits. When he does so, 2-5 are seen in their normal clothes, then shift back to their swimsuits.
After Numbuh 3 gets the snacks and Mr. Wink and Mr. Fibb lower their lifeguard chair robot, the umbrella laser shooter on top of it is gone.