In "Operation: E.L.E.C.T.I.O.N.S. (Enemy Launches Evil Campaign To Inflame Our Noble School)", the Kids Next Door are up against more than they bargained for when they try to prevent the Delightful Children From Down the Lane for dashing the school elections, especially when the situation involves eighth graders!

In "Operation: D.U.C.K.Y. (Dirty Unwashed Captain's Kowardly Yacht)", Numbuh 2's little brother, Tommy, trying to avoid taking a bath, finds himself on a ship with a captain who fears ever becoming clean. It turns out that he and his crew on the run from a giant rubber ducky who will make sure they're washed up if it ever catches them. In "Operation: D.I.A.P.E.R. (Drooling Infants Awarded Perilous Emergency Rescue)", Numbuh 1, Numbuh 2, Numbuh 3 and Numbuh 4, thinking that the babies at the hospital are being imprisoned so they can be turned into adults, 'rescue' them...

In "Operation: B.U.L.L.I.E.S. (Big Ugly Lunks Like Intimidating Entrapped Scaredycats", Numbuh 2 and Numbuh 4 visit an island habitat where a kid scientist keeps dinosaur-like bullies. He assures them that they are completely safe from the bullies, but it might not be just the bullies they have to worry about. In "Operation: F.I.S.H.Y. (Feline Invaders Swarm Headquarters Yearningly)", Numbuh 3's goldfish has died, and none of her fellow operatives have the heart to tell her. So while Numbuh 1 and Numbuh 5 try to get a new fish as a replacement, it's up to Numbuhs 2 ...

In "Operation: B.R.E.A.K.-U.P. (Boys Ruin Everything And Kreate Upset People)", Numbuh 4 uncovers an insidious baseball-like game where fragile objects are smashed... and the game's latest target is his mother's priceless vase! In "Operation: S.A.F.A.R.I. (Shots Are Fired At Rear Incessantly)", Numbuh 1 tries to run from a doctor and his cure for Numbuh 1's "moosebumps".

In "Operation: N.A.U.G.H.T.Y. (Ninnies Almost Undo Greatest Holiday This Year)", the Kids Next Door try to save Christmas when the Delightful Children From Down the Lane frame them for the theft of a gift-creating contraption created by Santa.

In "Operation: V.I.R.U.S. (Very Icky Research Under Sea)", Numbuh 5's sister Cree accuses her of a crime she never committed. In "Operation: O.U.T.B.R.E.A.K. (Overflowed Undersea Treehouse Bears Really Extra Awful Kontamintaion)", the KND tries to close up a virus spreading through a KND undersea lab.

In "Operation: C.A.N.Y.O.N. (Clear Area Need You Out Now)", the Toiletnator becomes intrigued when he sees the Kids Next Door's recent bizarre activity, such as transporting large amounts of cereal, milk, sugar and spoons to the Grand Canyon. Desperate to impress his fellow villains, he decides to take matters into his own hands and ruin whatever the Kids Next Door are planning. In "Operation: H.O.L.I.D.A.Y. (Hamsters On Leave In Disastrous Airline Yarn)", Lizzie is furious when she learns that the 'secret mission' Numbuh 1 was supposedly on was really a trip to ...

In "Operation: C.A.K.E.D.-F.I.V.E. (Centuries After Kalamity Enemy Dessert Found In Void's Emptiness)", it is once again the Delightful Children From Down the Lane's birthday. The Kids Next Door have been tipped off by an operative about the cake's whereabouts as floating up in space, where Father plans to use a 19th century birthday cake recipe to give his children the best birthday ever.

In "Operation: R.E.C.R.U.I.T. (Really Excitable Child Rookie Undergoes Impossible Test)", a wanna-be operative named Bobby is excited when he finds out he may just gain entry to the Kids Next Door, if he can pass a series of tests. But trying to complete the frustratingly hard tasks might reveal a completely different side of him. In "Operation: D.A.D.D.Y. (Dasterdly Adult's 'Do Degrades Youngster)", a Kids Next Door operative is given a horrible haircut by his dad, and tells Numbuh 1 that the same fate awaits his brother in the morning. Accompanied by a couple of ...

In "Operation: C.L.O.W.N. (Curmudgeon's Lackeys Outlaw Wacky Nonsense)", Numbuh 2, who prides himself on being the funniest student at Gallagher Elementary, is warned by a disgruntled clown and his henchmen to cease his silliness or else. But not being able to tell any jokes drives Numbuh 2 crazy! In "Operation: S.P.A.N.K.E.N.S.T.I.N.E. (Stuffed Puffy Animal Now Kruelly Enacts Nasty Spanking To Investigator's Notable End)", Numbuh 3's sister Mushi, after being grounded for life with no chance of TV because of Numbuh 2's detective work, harnesses the powers of Count ...

In "Operation: H.O.T.-S.T.U.F.F. (Hands Off Thermostat Says The Upset Father Furiously)", Numbuh 3 is freezing, but her father refuses to let her turn up the heat. When she does so anyway, the Sanban residence becomes so hot that it turns into a volcano which threatens to erupt if the other Kids Next Door operatives don't turn down the thermostat in time. In "Operation: M.I.S.S.I.O.N. (Many Incarcerated Scoundrels Secretly Implement Operative's Needs)", Numbuh 4 underhandedly arranges for some of the worst adult villains to be released from the Kids Next Door Arctic ...

In "Operation: ENGLAND (Evidently Not Getting Language Annoys Nigel Desperately)", Numbuh 1 is thrust into a mission to deliver a book to a library before it's too late, and soon discovers that this book is perhaps far more important than he thought. In "Operation: AWARDS (Attack Will Amazingly Ruin Dinner Show)", Sector V attempts to crash the Annual Villains' Choice Awards and Dinner Show, but this doesn't go exactly as planned.

In "Operation: LICORICE (Lost Island's Crop Of Red Irreplaceable Candy Endangered)", Numbuh 5 must team up with Stickybeard to save Heinrich Von Marzipan from a crew of skeletal licorice pirates. In "Operation: HOME (Hardly Ordinary Monkey Estate)", Numbuh 3 has second thoughts about sending her old Rainbow Monkey to a retirement home.

In "Operation: I.T. (Indecisive Time)", Numbuh 362 becomes frustrated with all the work involved with being Supreme Leader of the Kids Next Door, so she decides to give up her position. But everything goes horribly wrong when Father takes her place!