"Wolf In Peewit's Clothing" is a Season 3 episode from the Smurfs cartoon show.
In an old castle, an evil wizard named Radna has found a book that he says holds the key to making him number one in wizardry so that his evil powers and his castle will be restored. While looking through the ingredients in the book needed for the restoration of his powers, he comes across the mention of Smurf sweat and wonders where he will ever find it or even if the Smurfs exist. But as he realizes that without the Smurfs, his power restoration will be useless, he gets a visitor in the form of Peewit, the court entertainer who is looking for someone who will offer him dinner. Radna tells the visitor to go away, but when Peewit mentions who he is and that he is a friend of the Smurfs, the evil wizard gladly receives him and serves him a dinner to satisfy his appetite. In the middle of serving the meal's courses, Radna looks through his potions and sees wolf gravy, something that will only be effective during a full moon, but he is very eager to try it out. As Radna brings forth a plate of roast beef for Peewit, he offers him gravy to pour on his meat. After eating the roast beef with the gravy, Peewit compliments Radna on the meal and insists on paying his host. Radna says that it isn't necessary, and suddenly Peewit responds with a "Yes, Master" while in a hypnotic state. Radna sees that the wolf gravy is working, and tells Peewit that he will go to the Smurf Village on the night of the full moon and bring his master back three Smurfs, but until then he will forget that he has ever been with Radna.
Later on at The King's castle, Peewit's majesty is preparing for sleep and wants his entertainer to read him a bedtime story. Peewit starts reading but then dozes off until The King awakens him, but then he sees that Peewit is more able to fall asleep than he is and so goes to get a goblet of warm milk to help him relax. While The King is out of his bedroom, the full moon shines through the window and Peewit soon transforms himself into a werewolf, tearing the storybook he was holding. The King returns with his milk and sees the terror in his bedroom, calling for Sir Johan's help. The young knight awakens from his sleep and charges into the bedroom with his sword, seeing the werewolf eating The King's slippers before he dives out the window and disappears into the forest. Feeling relieved that the danger is gone, Johan goes back to sleep, commenting on Peewit being able to sleep through anything.
By morning, Peewit in werewolf form has traveled far into the forest and is now tired out, so he rests himself near a tree where he changes back to his human form. At this time, Brainy and Clumsy have gone out into the forest in order to find early morning mistweed when they encounter Peewit sleeping near the tree. Peewit awakens and asks the two Smurfs what they're doing in the forest before he wonders what he himself is doing there. Clumsy suggests that Peewit must have walked in his sleep, while Brainy says he must have ran in his sleep, because he's now near the village. Peewit says that he hopes he hasn't missed breakfast because he's starving.
Back at The King's castle, Johan goes to the door of Peewit's bedroom to wake him up for breakfast, only to find out that his friend is gone. He takes his horse Bayard out into the forest to look for Peewit, believing that his friend's disappearance is somehow connected to that of the wolf creature that paid The King a visit. By nightfall, Johan spots wolf tracks and decides to follow them with the light of the full moon shining down.
Around this time, the Smurfs and Peewit are all preparing for bed. They offer their human visitor a bunch of blankets to keep him warm during the night. After they have said their goodnights, the Smurfs and Peewit fall asleep. But as the light of the full moon shines down, Peewit is changed back into a werewolf and starts looking for three Smurfs to capture. He first grabs Brainy, then he grabs Smurfette, and finally he grabs Clumsy. Papa Smurf sees the wolf run off with the Smurfs in a sack and says that it must be Peewit under an evil spell. Hefty is ready to go after the werewolf, but Papa Smurf says he must go get some things from his laboratory.
Out in the forest, with Papa Smurf, Hefty, and Greedy carrying lanterns, they find a trail of wolf tracks and are about to follow it when Hefty hears a human coming. They dive into the bushes and see that it is Johan who is looking for both Peewit and the werewolf, also following the trail of wolf tracks. Johan asks the Smurfs if they have seen either Peewit or the werewolf, and Papa Smurf says that they are both one and the same. Meanwhile in Radna's castle, the evil wizard commends Peewit for his success in bringing him three live Smurfs for his power restoration formula. He offers the werewolf a reward -- the best cell in his dungeon, as he claps irons on Peewit's wrists.
By morning, Johan has his horse rest, promising the Smurfs that he will find Peewit and prevent him from doing any harm. Papa Smurf's concern, however, is that Peewit will be kept from harming himself. As for Peewit, he finds himself back in his human form and surprised to find that his "sleepwalking" has now put him in prison. While he cries for Mama inside Radna's dungeon, the evil wizard has the three Smurfs running themselves ragged in a cage, causing them to perspire so that he can collect enough Smurf sweat for his power restoration formula.
Later on, Johan and the Smurfs reach Radna's castle, which Papa Smurf recognizes as the home of a once-powerful evil wizard. Upon reaching the castle's entrance, Johan finds a strong enough vine he could use to climb his way up to a window through which he can sneak his way into the castle. But then night falls, and with the full moon shining, Peewit becomes a werewolf again and breaks his bonds. Johan hears and sees his friend as a werewolf by the window, who then chomps on the vine and causes Johan to fall, barely managing to rescue himself and the Smurfs by grabbing onto a ledge. The four of them leap inside through a nearby window, but as they look for a way they should go to find the Smurfs, the werewolf comes toward them. The three Smurfs go off to find the others while Johan tries to capture Peewit with his cape, only for his werewolf self to tear through it, causing the young knight to flee.
The three Smurfs find Radna's laboratory and see the three captured Smurfs running inside a cage to give the evil wizard his Smurf sweat so his evil powers can be restored. While Papa Smurf wonders what to do, Johan manages to trap Peewit inside a room by leaping onto a chandelier and then kicking the door closed before the chandelier breaks off from the ceiling. Radna hears this and goes to check out where it came from, and with the distraction Hefty grabs a bell rope and swings up to the cage to let the three captured Smurfs loose. Radna encounters Johan near the room Peewit is trapped in, but he doesn't stay trapped for long, as he bursts through the door and chases after Radna, tearing through his spellbook in his pursuit. The evil wizard also sees that his captured Smurfs are gone, and as they dump the bottle of Smurf sweat on the floor and break it, he sees that his plans to restore his powers are ruined.
Johan now wonders how they can bring Peewit back to normal to save Radna from his own evil creation. Papa Smurf says that he needs to have Peewit open his mouth so he can feed him a garlic bud. John tried tickling the werewolf, and soon he is distracted with all the giggling, allowing Papa Smurf to throw the garlic bud into Peewit's mouth. Soon the young entertainer is back to normal and wondering if he will ever stop sleepwalking. Johan assures his friend that his problems are over, thanks to the Smurfs. Meanwhile, Radna is pounding the floor, frustrated that he will never become a number one evil wizard before he realizes that maybe he can become a good one.
Papa Smurf counts up the Smurfs that are with him and wonders where Greedy is. He is soon found tasting the spilled contents of a bottle of wolf gravy, and after that the Smurfs see that he is changed into a werewolf. Carrying him safely inside a sack, the Smurfs take him to a smurfberry bush to feed his appetite until Papa Smurf shows up with a garlic bud that he feeds to Greedy, instantly restoring him to normal. With the village chef letting out a powerful garlic-smelling burp, Papa Smurf says that now he needs to start looking for some wild mint before he faints.
- The title of the episode is based on the phrase, "a wolf in sheep's clothing," which in turn is a literary allusion to Matthew 7:15 in the Bible, which reads, "Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves."