When Numbuh 1 is fishing with his dad, Numbuh 86 and her group appear and tell him that he's been scheduled for a decommissioning! Although he escapes, his teammates are taken to be decommissioned, so he has to enlist the help of Numbuh 2's little brother Tommy to try and save them! Unfortunatly, he is too late, but can he still save the Moon Base from a fiery demise?moreless
Operation: D.O.G.F.I.G.H.T.: Numbuh 2 has always been one of the best pilots in the organization - but one day while taking his 2X4 aircraft for a spin, he's shot down by a mysterious child pilot with a 2X4 plane of his own. 2 seeks revenge, but the pilot is untouchable, and manages to shoot him down out of every aircraft in the team's arsenal! Considering giving up, piloting, Hoagie finally finds a way to defeat the pilot - only to discover that his supplier has been fooling them both into fighting each other in a plot to destroy every chili dog in town! Can the dueling dogfaces prevent this mystery meat massacre?!
Operation T.R.I.P.: Father learns that Numbuh 3 is traveling to her homeland to meet up with the secret Japanese branch of the Kids Next Door; so he sends his best spies, the Interesting Twins From Beneath the Mountain, to trail Kuki and find the location of the Japanese agents' hideaway so an attack can be made. But when the two young spies trail 3, a combination of their incompetence and her natural good luck impair them at every turn! What will be the outcome of this stealthy struggle in the Land of the Rising Sun?!
Operation: B.E.A.C.H. The KND take a vacation to the beach (and Numbuh 1 promptly leaves, since he hates the place), where Numbuh 3 is quickly kidnapped by the armored Knights of the Round Towel, who drag her before King Sandy, a miniature monarch who quickly falls in love with her! Naturally, the concerned Numbuhs 4 with Numbuhs 2 and 5 confronting the beachcombing brat in his enormous sandcastle... but they are soon overwhelmed. Can the KND topple this tiny tyrant before high tide?
Operation: U.N.D.E.R.C.O.V.E.R.: The Delightful Children have the team right where they want them (again), when suddenly, the helmet headed member (his name revealed as Lenny) pushes the wrong button on their vehicle, ruining the villains' plans. The KND start to head home, when they are called to the Moon Base, where they meet with Numbuh 274... and Lenny himself! The Delightful Child claims that he is the reason that his siblings plans always fail, and that he intends to help the KND organization by cutting off the Delightful Children's supply of coffee, the source of their evil power. Thus, the KND and Lenny travel to an offshore coffee drilling rig to make a pre-emptive strike... but could this all be, as it most likely is, a double cross? And if so, who is double-crossing who?
Operation: T.H.E.-S.H.O.G.U.N.: Numbuh 2 and Numbuh 4 visit the grand opening of a cheese-themed restaurant which seems to have a big problem - an appalling lack of cheese! And when 2 reveals that he's brought his own, the source of the problem is revealed, when the operatives are kidnapped by cheese headed ninja, and then dragged before the Cheese Shogun, a mad martial artist who holds cheese to be more valuable than gold. Can 2 and 4 defeat this insane samurai and escape his deadly dairy dojo?!
Operation: C.O.L.L.E.G.E.: Numbuh 1 hears word that a ten-year-old prodigy has been accepted into a prestigious British College, and fears that the adults seek to remove his brain. With the rest of the team refusing to give up their day off, 1 travels across the Pond himself - only to find that the report was a ruse by the misunderstood mad scientist Professor Triple Extra-Large! The snow-cone expert has come close to perfecting his masterpiece, and now needs a test subject who is immune to ice cream headaches - and 1 fits the bill. 1 is eager to help, but when his well meaning friends try to launch a rescue mission, the Professor goes from mad to plain angry! Can they escape this chaotic collegic catastrophe?!
Operation: S.U.P.P.O.R.T.: Numbuh 5 is sick at home with the flu, and Numbuhs 1 and 2 take it upon themselves to protect her from the enemy. While at her house, her father lets it slip that teenage sister Cree is wearing a training bra! Ever suspicious of teenagers, Numbuh 1 figures that this odd device must be "Battle Ready Armor", and becomes determined to discover the workings behind it. But when the two of them are discovered, can even the Kids Next Door survive the wrath of a humiliated teenager?! And could there be more than meets the eye in this lingerie liason?
Operation T.A.P.I.O.C.A.: On a seemingly routine mission, Numbuh 2 seizes a truckload of disgusting tapioca pudding from a trio of masked teenagers; unfortunatly, when trying to dispose of it, he plants it right in the middle of the treehouse! Now the team is up to their necks trying to clean up the putrid pudding, and the original teen-age owners still want it back! But why? Only Numbuh 2's grandmother knows for sure...
Operation: S.P.A.N.K.: After spending a stretch in the slammer for spanking the wrong child, the vampiric villain Count Spankulot vows to use his abilities to help children instead of harm them, and approaches the Kids Next Door with an offer to join them! But when the former Bounty Hunter of Bottoms turns out to be more annoying now than he ever was as a villain, how will the KND get rid of the Pesky Paddler?
Operation: D.A.T.E.: The Delightful Children From Down the Lane are holding a social, and the KND are invited! Smelling a rat, Numbuh 1 and the team decide to go for a reconnaissance mission - and as the only one without a date, he brings Lizzie along. But when the Delightful Children spring their trap, Lizzie becomes more of a hindrance than ever. Will Numbuh 1 prevail? Will his relationship with Lizzie survive?!
Operation: C.A.T.S.: Numbuh 4 accidentally destroys Numbuh 3's favorite toy, and then lands himself in the clutches of the Creepy Old Cat Lady and her billions of cats! His fellow operatives embark on a rescue mission, but Numbuh 3 refuses to go. But will she eventually forgive Numbuh 4 in time to save him?
Operation: P.O.P.: When the drinking age of root beer is raised to 13, the Kids Next Door swing into action, delivering soda to speakeasies for youngsters. But soon the Kids discover the prohibition's leader, Mr. Fizz, has something even more sinister in store. Can the Kids Next Door stop Fizz from bottling up children everywhere?
The frustrated Delightful Children from Down the Lane turn to their Father for help destroying the KND, who are almost defeated after they subsequent successful attack. With their leader gone, treehouse destroyed and faith shattered, the KND are forced into a showdown with their most dangerous foe ever.moreless
Operation: Q.U.I.E.T.: Numbuh 1 has to have a good night's sleep for a KND Award Show and Numbuh 5 tries to keep it quiet. But what happens when every single villain they've ever faced so far tries to invade the treehouse?
Operation: R.A.I.N.B.O.W.S.: Numbuh 3 learns that her Rainbow Monkey dolls are based on real creatures and plans on finding them at Rainbow Monkey Island.
Operation P.I.A.N.O.: Numbuh 4 discovers a shipment of "Type P" kid torture devices--the P meaning pianos! On the mission, he gets injured and the rest of the KND have to continue without him. But Numbuh 4 goes along anyway and bungles the second mission as well, resulting in all of Sector V getting badly hurt as well. As they heal, the Hamsters Next Door take over for them!
Operation Z.O.O.: Many of the kids in town, are captured by an evil zoologist who tags them and puts them in cages at the kids zoo. The KND are among them and if they want to escape, they'll need to work alongside the Delightful Children from Down the Lane!
Operation T.O.M.M.Y.: Numbuh 2's little brother will do anything to hang out with him, even if that means forming an alliance with the Common Cold.
Operation C.H.A.D.: When operatives from the KND international organization are neutralized by Mega Mom and Destructo Dad, The KND team up with the legendary operative Numbuh 274 to ground the powerful parental enemies.
The KND are chosen to star in a show on a 'kid-centric' network that's run by an adult executive who has the appearance of a baby.
Can Numbuh 1 stop a camp counselor without the help of Numbuhs 2 and 3, who've taken on the role as parents of an orphaned baby skunk?
Operation: T.H.E.-F.L.Y.: A fly finds its way into the KND treehouse and gets different reactions from Numbuhs 1, 2, 3, 4 and 5.
Operation: P.O.I.N.T.: All the teenagers in town are going to a place called "The Point" and Numbuh 1 suspects that they're being turned into adults in order to make kids' lives more miserable. So, the KND stage a raid at the point's secret location, only to find thing aren't what they expected.
Operation: L.I.C.E.: Numbuh 5 goes on a mission to steal nachos at the Delightful Children from Down the Lane's mansion. She makes a narrow escape, getting her hat in the nick of time and returns to the KND Treehouse, sharing the goods with the others. But before she's able to enjoy the nachos with melted cheese, her head becomes very itchy, and discovers a giant louse has stowed away on a different hat that the DCFDTL swapped with hers. Eventually, the lice multiply and become a danger to the KND, who discover the only way to get rid of them is with nacho cheese.
Operation: L.I.Z.Z.I.E.: Numbuh 1 gives the others the day off claiming he's going on a secret mission. The others go to the carnival only to discover he's there, too--with a girlfriend! Nigel reluctantly introduces them to Lizzie, who gets angry with him when he doesn't acknowledge their relationship in front of them. The next day, Lizzie gives him a gift, which the other KND discover is a boyfriend helmet, that she uses to control him into making him do whatever she wants. Can Numbuhs 2-5 save their leader from his possessive girlfriend?
Operation: O.F.F.I.C.E.: Numbuh 4 reluctantly accompanies his dad to work uncovers a scheme including Rainbow Monkeys and screaming girls plus a one way trip to Pluto!
Operation: A.R.C.T.I.C.: The Kids Next Door journey to the arctic and hope to uncover a weather control device from a mad scientist who wants to put an end to snowy days.
Operation: T.U.R.N.I.P.: When the KND treehouse is flooded by turnips, the gang must travel to the source where they encounter a giant turnip that continues growing out of control.
Operation: M.I.N.I.-G.O.L.F.: Numbuh 2 challenges mini-golf champ Rupert Puttkin to a match and wins. But soon, he realizes Rupert has a grand scheme in his golfbag when he plans to shrink the entire planet Earth into his own golf ball!
Operation: P.I.R.A.T.E.: Stickybeard and his candy-stealing pirates invade the KND treehouse, stealing all their candy, including Numbuh 5's secret stash, and Numbuh 5 herself! Can the rest of the kids recover their teammate and their candy?
Operation C.O.W.G.I.R.L.: The Kids Next Door are on the run from Mr. Wink and Mr. Fibb, when they're rescued by Lasso Lass, the only member of the original anti-adult super squad "The Cowboy Kids' Club" who's grown old, but not grown up. She offers to help the Kids recover Fibb and Wink's secret weapon ("The Dome"), but can the kids trust an adult, even one who's still a kid at heart?
Operation: N.O.-P.O.W.U.H.: When Numbuh 3 releases the hamsters powering the treehouse, Gramma Stuffums attacks! Will the Kids Next Door be able to fend off this foody fiend?
Operation: T.E.E.T.H.: When the KND get attacked by Knightbrace on the way to the candy store, they must use the evil dentist's own abilities against him!
Operation: I.-S.C.R.E.A.M.: Adults are running around with ice cream trucks, but don't give any ice cream to the kids. So the Kids Next Door bust them up and get the password for the ice cream headquarters, then are soon confronted with the Delightful Children From Down The Lane.
Operation: C.A.N.N.O.N.: Numbuh 1 has to go to a theme park with his parents for the day and leaves the other Kids Next Door operatives to watch the place. Soon, they're bombarded with evildoers, including the Delightful Children From Down The Lane. Later that day, after the DCFDTL are told to go back home, Numbuh 5 accidentally suggests making a huge clam cannon. Numbuh 4 claims the roll of leader, then uses his new status to order the others to build the clam cannon.