Randy and Howard follow Theresa Fowler (voiced by Sarah Hyland) and the rest of their classmates to a cool new club downtown only to discover that the Sorceress (voiced by Jennifer Tilly) has returned to seek revenge on the Ninja.

Randy, Howard, and all the boys at Norrisville High are entranced by the new girl in school named Amanda Levay. Little do they know that she's the Sorceress (voiced by Jennifer Tilly), the Sorcerer's long lost love in disguise where she has plans to free the Sorcerer.

Randy and Howard accidentally stumble back in time and accidentally stop the original Ninja from stopping the Sorcerer.

The Wave Slayer relays are occurring in Norrisville as Randy and Howard accidentally wrecks the Wave Slayer where an accident injures Buttermaker and causes Howard to take his place. The Sorcerer takes the opportunity to Stankify Buttermaker (voiced by Sterling Knight) into an aquatic monster that attacks the opposing team.

When Randy and Howard's video game battle gets out of hand, the Ninja must save the town from a giant robot.

When a robot disguised as a rival school's chess team member crushes Norrisville High's record - and their spirit, a mass stanking breaks out.

The Ninja fights a lizard, which copies a sample of his snot. Later Randy and Howard attend a party Bash is throwing, but it's a scheme so McFist can find the ninja by sampling everyone's snot bombs and matching it to the ninja.

After a fight between Randy and Howard, a monster attacks during the school's annual routine "monster drill" where Howard is pretending to be the ninja. Randy must find a way to get to his mask and to apologize to his friend.

Randy Cunningham looks for the Skunk Pine in order to restock his smoke bombs. When Randy finds the Skunk Pine, it is stolen by Hannibal McFist to use as a Christmas tree party at McFist Industries. Randy also discovers that Howard is at Hannibal McFist's Christmas party when his father's company was bought by McFist Industries. When Randy infiltrates the Christmas party as a Ninja Santa Claus, he ends up fighting a robotic snowman and an army of robotic Christmas Elves in order to restock his smoke bombs.

Randy helps students escape from Detention Island.

Randy and Howard seek revenge on a French exchange student who stole their Internet video fame - only to cause him to stank out and create a scene they weren't expecting.

Randy must stop a former Norrisville Ninja-turned-nemesis from recruiting an army intended to destroy the Ninja.

Randy must go with Howard to CluckFest under the threat of Bash Johnson. This won't be easy for Randy since he is afraid of chickens. Meanwhile, Hannibal McFist and Willem Viceroy III unleash a fear-pooping robotic rhinoceros called the Rhinosaurus that forces everyone to confront their worst fear as part of their plot to find the Ninja's greatest fear and take advantage of it.

During Ninja Day, McFist schemes to steal the spotlight by introducing a new hero - himself; the real Ranginald is in danger of McFist's fury.

In order to score a limousine ride with soccer super star Pitch Kickham (voiced by Simon Pegg), the Ninja swipes a pair of shorts to help him win a shoot-out competition. When McFist sends an I.D. Bot to find the shorts, Randy's identity is compromised and Howard must take Randy's place in the competition.

During "Ninja Day" McFist schemes to steal the spotlight by introducing a new hero - Himself.

During the 50th Anniversary Celebration of McFist Industries, the Ninja outs McFist as a villain to the entire town. But with his cover blown, McFist is finally able to focus all of his power on destroying the Ninja.

Randy accidentally brings the mad scientist back to life.

Randy and Howard wonder why everyone in town is turning into zombies.

When Randy and Howard are forced to share a lunch table with the outcast group "Der Monster Klub", Randy accidentally tells them how to get people stank'd, and they realize these oddballs are playing a dangerous game that could destroy the whole school even when the Sorcerer gets involved when some of the members get depressed.

Randy Cunningham, a 9th grade kid, becomes a ninja and is to protect Norisville High School.

Randy and Howard become judges for their school's talent show and Randy tells Howard that he should be "the mean judge." But the Sorcerer takes this chance and makes all the failing acts monsters.

When Randy discovers that the Norrisville philanthropist, Hannibal McFist, is his enemy, he has a hard time trying to convince Howard that the one they believed to be their hero is actually an evil villain working with the Sorcerer.

Randy and Howard find a note under their school.

A Mexican death bear threatens the school.