Professor Curio had a break in late last night, but the robber was a failed ninja from a ninja academy. Kirby tries to help him learn to be better. It seems that the scroll has another admirer, King Dedede.
|Spoiler alert: The following section contains plot-specific details.(Skip Section)|
The next morning, Curio reports what he saw to Chief Bookem, while Tiff, Tuff, and Kirby listen nearby. Curio explains that it's an ancient scroll that once belonged to ninjas, and they used them to pass down their fighting methods to other ninjas. Tuff thinks that ninjas are cool, and decides to start pretending to be one. Kirby also likes the idea.Meanwhile, King Dedede and Escargoon visit Cappy Town, suspicious of the Cappies' actions, because they have all seemingly disappeared from town. The truth is all of the Cappy kids are pretending to be ninjas (even some of the grown-ups are participating), and suddenly ambush Dedede with toy ninja stars, and then run away. He gets mad and yells at them, attempting to scold them all, but they just ignore him, except for them leaving miniature spiky stars all over where Dedede and Escargoon are standing. Upon regaining their balance, they question the Cappies and find out they're wearing what the ninjas wear, inspired by the incident of Curio's scroll.
Later, the duo go to Curio's place to look at the scroll, and they tell him a distraction, and quickly swap the scroll with a fake so they can learn how to be real ninjas. Tuff, Kirby and his friends were watching however and call them out. Dedede threatens Curio with imprisonment so he can get away with it, but after he leaves, the thief from last night appears and chases after him.
They begin learning how to be ninjas at Castle Dedede. Tiff is wondering why everyone's so into ninjas nowadays since there are none left, but Meta Knight appears and tells her that she is wrong. He explains that ninjas were strong warriors that fought alongside the star warriors in the war against Nightmare. They were famous for their incredible skill in battle, and he believes that some of these ninjas are still around. He also tells Tiff the story of Yamikage. According to Meta Knight, Yamikage betrayed the star warriors to work for Nightmare Enterprises and Meta Knight is worried that he was the ninja that tried to steal the scroll, considering he was never defeated.
Meanwhile, Tuff and his friends, including Kirby, start taking learning how to be ninjas more seriously now and want to steal the scroll back from Dedede in order to learn more about being ninjas. That night, he and Kirby sneak inside the library where Escargoon is sleeping next to the scroll, so they quietly snatch it and walk through the hallway, but Kirby notices the same ninja that tried to steal the scroll! Except for this time, his cloak color is much more visible, and it's actually red. They yell at the fact that it's a real ninja, however, the figure runs away. This causes Escargoon and King Dedede to wake up and demand they give the scroll back, but then Tiff, Lololo and Lalala arrive due to the noise. Tuff claims that he saw a real ninja hiding but he ran away. Dedede and Escargoon outright don't believe him, and Tiff, Lololo and Lalala didn't see him. After looking around a bit, they spot him clinging on to the ceiling, but he can't hang on and falls down on Tuff, causing him to drop the scroll. He quickly grabs the scroll and runs away with it, and the others chase him down.The ninja escapes the castle with the scroll in hand and goes to Cappy Town, but is confronted by the Cappies while Tuff, Tiff and Kirby chase after him, but he keeps running and evading capture, until he teleports to a tree branch, and can't hold on and falls off in front of the trio and leaves the scroll hanging. He guards it and threatens to throw real ninja stars at them, however, they all miss by a long shot. He then admits that they're plastic and starts crying. Finally, he explains to them that the scroll is actually his report card from ninja school, and he lost it one day. Apparently, he (actually named Benikage) was such a bad student he had to drop out, and all of the red triangles on the scroll basically mean "F". Tuff decides to teach Benikage how to be a ninja, so he won't be a failure anymore.
The next day, King Dedede still believes the scroll is real, and orders Meta Knight's old enemy Yamikage from Nightmare Enterprises to steal back the scroll. Meanwhile, Benikage and Kirby are doing some target practice, but they're not doing so hot. Finally, a ninja star hits the target, and Tiff and Tuff congratulate them, but neither of them threw it...It's revealed that Yamikage did it, and he's come to reclaim the scroll. Tuff tells them the truth that the scroll is actually a bad report card, but Yamikage ignores and still wants it, but Benikage grabs it and runs off with it, and Yamikage appears in front of him, and they duel for it. Benikage is overpowered, and he loses the scroll, and King Dedede grabs it. When Yamikage throws one last knife at him though, Kirby rushes in and inhales it, and becomes Ninja Kirby.
After his transformation, Kirby has a sword duel with Yamikage, and can even throw ninja stars properly now. Yamikage unleashes wind from his sword, causing Kirby to become disoriented, and allowing Yamikage to hit him and cause him to fly back a little, and just when Yamikage is about to perform the final blow, Kirby teleports away and appears behind him. He grabs Yamikage and throws him down (similar to Backdrop or Suplex), causing him to be KO'd, and Kirby falls back down without his ability. In a cloud of smoke, Yamikage disappears, but not before telling him that he'll have his revenge one day.
Later in the day during sunset, Benikage explains to Tiff, Tuff, and Kirby that he is inspired by what happened that day and has decided to start over in his ninja class and work harder, and the episode ends with Benikage teleporting away, but he accidentally appears in the river instead, and swims away.
|End of spoilers|