Following the events of "Karate Clumsy", the time-lost Smurfs make themselves at home in the mice village of Japan, with Smurfette, Handy, and Brainy watching a demonstration of karate by a male and female mouse. The female makes an attack move called the "bowing crane", but the male mouse counters it and sends her flying away, to which she says the move can also be called the "crushing crane". Brainy thinks that he is a master of the martial arts and is ready to show it, until he sees the female mouse's hands move like lightning and becomes fearful. Meanwhile, inside Mouse Master's house, he and Grandpa Smurf watch Papa Smurf as he spends his time assembling the crystals in a formation that will hopefully get them home. He says he has only a few more crystals to place and he must be very careful. Unfortunately, Brainy goes flying through the paper window of the house and lands on the table, scattering the assembled crystals. Smurfette looks through the hole in the window and asks Brainy what he calls that move, and Brainy simply says "painful".
Mouse Master takes the two elderly Smurfs outside to a garden where he says it will "protect the caterpillar from the woodpecker", meaning that nobody will bother Papa Smurf here while he tries again to assemble the crystals. However, Brainy shows up, eager to make sure nobody else bothers his esteemed leader and father figure while he is at work. As Brainy is about his sit upon a rock, Mouse Master tries to warn him not to sit on it, but after he sits down, the elderly mouse says that it's not a rock but a slumber bug. Suddenly the "rock" rises and reveals itself to be the bug, causing Brainy to jump away in fear, but in doing so he lands on Papa Smurf and catapults him right in front of the bug itself. Mouse Master and Grandpa Smurf watch as the bug bites Papa Smurf in the tail, and as the Smurfs gather around the village leader to see if he is all right, Mouse Master says that the slumber bug's bite will cause Papa Smurf to fall into a deep sleep from which he will not be able to awaken. Papa Smurf rises and assures his little Smurfs that he's only a little bruised from the bite. Mouse Master warns not to let Papa Smurf fall asleep, but before any Smurf can do anything, he is already slumbering.
While a few Smurfs try to help Papa Smurf to awaken by walking him around, Brainy declares himself to be the new fearless leader in Papa Smurf's place when his own words of "encouragement" end up betraying him. Mouse Master tells Grandpa Smurf of one way that Papa Smurf can be awakened: that if he is bitten by the bonsai beetle, he will awaken to the rising sun, according to ancient legends. However, if Papa Smurf isn't bitten before the second sunset, he will remain asleep forever. With Grandpa Smurf realizing the urgency, Brainy says that he will lead the expedition.
Mouse Master tells the young Smurf that he will find the bonsai beetle to the east in the secret garden at the Palace Of The Rising Sun. He also warns Brainy to beware of Carpzilla, which Brainy assumes is talking about a small fish in the picture Mouse Master was holding in his right hand. But then Mouse Master unrolls the scroll in his left hand and shows the real image of Carpzilla: a fearsome beast of a fish with lots of sharp teeth. This makes Brainy balk at the idea of leading the expedition as he tries to talk his way out of being part of it. However, after the Smurfs start off and Brainy tries to offer his advice to the mice in the village, only to find himself booted out of it, he decides he would rather lead the expedition after all.
Sometime later, as the Smurfs reach a lake, Smurfette sees what appears to be the Palace Of The Rising Sun. Grandpa Smurf sees that if they try to go around the lake to get to the palace, it will be sunset by the time they get there, so the best way to get there sooner is to go across the lake on a raft. Brainy admonishes Grandpa Smurf by saying he should be the one to give the orders, and Grandpa Smurf tells Brainy to do it quick because Papa Smurf is fading fast. Brainy then gives the orders to build a raft, and so Hefty and Handy leave Jokey in charge of keeping Papa Smurf awake while they lend their strength and expertise in raft-building.
Soon the Smurfs are rowing across the lake, trying to keep Papa Smurf awake through various means while also trying to reach the palace on the other side. But then the waters become troublesome as the monster fish called Carpzilla emerges from below, ready to have a Smurf dinner served on a bamboo platter. The Smurfs paddle like crazy to escape their dinner date with the fish when he suddenly dives back down, making the Smurfs cheer until they see him suddenly emerge again, and then they resume the frantic paddling, causing Brainy to hang on for dear life as he falls into the water.
Painter comes up with an idea of getting rid of Carpzilla: with a chunk of wood he pulls from the water, he quickly paints the image of a fish on it and feeds it to the monster fish. He takes the bait, but he also stirs up the water by rotating in a circle before he sends the Smurfs and their raft flying to the shore by swatting his tail at them. They are safe and all together, but unfortunately they still have a way to go to get to the palace.
After a while of walking, Grandpa Smurf says that they should make camp and get some sleep before hiking up the mountain. Smurfette asks how they can sleep and make sure Papa Smurf stays awake, and Brainy tells her that he has selected Lazy to be in charge of watching Papa Smurf while the others sleep, since he already has enough sleep. But since Lazy himself can't help being asleep himself, Handy comes up with his own way to keep Papa Smurf awake: a self-activating alarm that triggers a banging of a pan when his head falls upon a pole. By morning, when the Smurfs rise and pull the plugs out of their ears, they set Papa Smurf upon a big green rock and then decide who's going to be carrying him when they notice that the "big green rock" has sprouted legs and is now carrying away Papa Smurf.
The Smurfs see that this "rock" is a turtle and chase after it, pushing past Brainy as he tries to offer his own advice on the situation at hand. Hefty grabs the turtle by the tail, which gets its attention to the point where it's snapping at Hefty. He grabs the turtle by the neck and wrestles with it, shaking Papa Smurf in the process, until the turtle pulls his head back into the shell, taking Hefty with it. The turtle shell bounces around with Papa Smurf still on it until Papa Smurf falls off and the turtle has been denuded of its shell. Hefty emerges from the shell wiping his hands off, saying that will teach the turtle not to mess with him.
As the Smurfs proceed up the mountain on the path that leads to the palace, a rotund man by the name of Dojo the gardener is busy in the secret garden trying to do karate moves as part of his exercise to get into shape before the Emperor arrives. He soon does, upon a litter carried by blindfolded guards who pass through the garden by a sliding hedge entrance, only to fall off and scold his men for their perceived clumsiness. He tells them that they are blindfolded because nobody but him and Dojo are to set eyes upon his royal garden. But then the Emperor's concerns turn to the appearance of the garden itself, telling Dojo that if he finds in it that's out of place or even one insect when he returns, he will have the gardener's head. After the Emperor leaves with his guardsmen, Dojo turns and sees that the bonsai beetle is at work trimming away the foliage of the bonsai trees in the garden. The fat gardener gives chase to the bug, hoping to squash it before it does anymore damage, but so far he hasn't caught it.
Meanwhile, the Smurfs have reached the outside of the secret garden and see that it is a maze to be navigated if they ever hope to find the bonsai beetle. Brainy chooses to take the lead, claiming to be an expert on navigating mazes, and so he hands off Papa Smurf to Clumsy for him to take of while he himself enters the hedge maze ahead of the group. Brainy claims that he will have the Smurfs through the maze in no time, with Clumsy trailing behind trying to carry Papa Smurf by himself. However, after a while of aimless wandering, Brainy is ready to throw in the towel when he backs into a branch that activates the sliding hedge passageway, helping the bespectacled Smurf to regain his confidence in the midst of unbelievers as they now enter the garden.
At that moment, Dojo is still contending with the bonsai beetle taunting him as it continues to evade him and his katana swings. It dives down into a small hole under a hedge, and Dojo brings a jar in hand with him, ready to capture the bug as it reemerges. On the other side of the hedge, the Smurfs approach it with Clumsy still carrying Papa Smurf, and Smurfette saying that it is almost sunset. Grandpa Smurf tries to tell the other Smurfs to keep it down as he hears the bonsai beetle nearby, saying that they don't want to scare him off. But as Brainy turns and walks off while trying to add his two cents in, he stumbles right into the face of the bonsai beetle and scares it off. The Smurfs now chase the beetle as it goes back through the hole in the hedge it had traveled, except that Dojo captures the Smurfs inside the jar instead of the beetle.
The fat gardener looks at his captives and wonders what kind of beetles they are, and Brainy tries to tell them that they are Smurfs, not insects. Dojo doesn't care what they are, as he sees them as little blue pests that he must get rid of before the Emperor returns. Smurfette sees Dojo raise up his katana in preparing to squash the Smurfs in the jar like bugs and quickly throws a rock that shatters the jar, freeing the Smurfs long enough to hide from Dojo. Then the bonsai beetle returns to distract Dojo's attention towards getting rid of it. Grandpa Smurf sees that they need to keep Dojo from squashing the bonsai beetle if they're going to save Papa Smurf, and Hefty offers to swing into action and make the big human fall, but he only bounces right off Dojo's belly and swings back to knock Brainy into a flower that his behind is stuck in. Handy and Painter use a vine and pull on it to make the gardener fall when he passes their way, but they also make him fall right onto the bonsai beetle.
Dojo gets up and sees that his bug problem is now taken care of, but soon he hears the Emperor returning, and he quickly races to where his litter enters to bow down and beg his forgiveness. However, the Emperor sees that the garden's appearance has improved, for he now likes the tiny trees he sees in it. He gives Dojo his highest praise and tells him that he now wants all the plants and the trees in the garden done in the same way. He also lets the guards remove their blindfolds, for he has decided that he will let all who wish to come into the garden and gaze upon the beautiful tiny trees in it.
After the Emperor leaves (with the guardsmen still unable to carry him properly through his garden), Dojo now wonders how he will be able to do the work of trimming the trees the way the Emperor wants it with the bonsai beetle now dead. Grandpa Smurf shows up saying that it's not dead, that all he needs is the Pick-Me-Up Pansy to awaken the bug, a flower that has been extinct for centuries. Dojo tells Grandpa Smurf that he's wrong and shows them to the flowers that Brainy is still stuck inside. Dojo plucks one of the pansies and gives it to Grandpa Smurf, who sprinkles its pollen into the mouth of the bonsai beetle, causing it to awaken. By that time, Jokey and Grouchy manage to pull Brainy and the flower off the stem to free him, and the bonsai beetle sees the flower's center on Brainy's behind and bites it, causing Brainy to talk so fast.
From this, Painter comes up with a way to lure the bonsai beetle into biting Papa Smurf. He paints a picture of the pansy's rings around Papa Smurf's tail, then a few Smurfs bring him as close to the beetle as they can to attract its attention. The bonsai beetle zooms in and bites, causing Papa Smurf great pain as he awakens, wondering what's going on. Brainy tries to explain the whole situation, but he is still talking so fast that the others have to silence him. Meanwhile, Dojo is honored to have the bonsai beetle working for him to help make the Emperor's garden a beautiful place to visit.
Mouse Master is pleased to see Papa Smurf awake upon his return to the mice village. Papa Smurf asks if the slumber bug is still in the garden, and as Mouse Master wonders why Papa Smurf should ask that, Brainy is seen arriving with a gag over his mouth as he continues to jabber on and on.
- A different art mistake happens in this episode: after Papa Smurf is bitten by the Japanese slumber bug, his kimono fails to cover the front area below his waist.