Sassette is in Smurfette's house admiring herself in the mirror as she is wearing one of Smurfette's dresses and hats, hoping Smurfette wouldn't mind her borrowing her clothes while she says it's about time she started dressing like an adult. Then, she hears Snappy to ask if she is ready to play smurfball, but she says no as she is dressed like "a big Smurf". Nat asks why as it is more fun to be a Smurfling. Snappy agrees and tells her to take off Smurfette's dress and start playing. Sassette still refuses, saying she's much too old to be playing with a bunch of Smurflings. She throws the ball back to them, hitting the heads of Nat, Snappy, and Slouchy.
Meanwhile, Papa Smurf is with Smurfette watching her water her flowers, saying the plants have grown big and strong in a very short time. Just then, Sassette comes to Smurfette, wanting her to look at how grown up she is. Smurfette likes the dress and Sassette tells her she borrowed it from her. However, she slips in water and falls, leaving the dress covered in dirt and water. This leaves Smurfette sad and walks off crying. Sassette is sad, telling Papa that she just wanted to be grown-up. Papa tells her "All in good time" and says its fun being a Smurfling, so she should enjoy it while she can.
Later, Sassette is in the forest dragging her Smurfy Lou doll, mad as she can't have a good time when everyone thinks that she's a Smurfling. She then hears Denisa crying near a log and asks her what's wrong. Denisa tells her that her mom told her she could have a party in Lord Balthazar's castle, but when she invited the Grackle sisters, they turned her down. After she massively blows her nose (blowing Sassette away), she tells her that they wouldn't want to hang around with someone like her. Sassette says she knows just how she feels as everyone treats her like a little Smurfling. Denisa is surprised and invites her to her slumber party and Sassette happily accepts. Denisa says to meet her at Lord Balthazar's castle as she walks away, with Sassette saying she'll be there.
Meanwhile, in the Grackle sisters' house, their mother calls them. When they come in, their mom calls them out for throwing away Denisa's invitation. One of the daughters tells her that they don't even like her, with the second saying she's a boring brat, and the third saying she acts like a little kid. The mom is mad now and tells them that Denisa comes from a powerful, rich family, including Balthazar, who she has a crush on. She forces them to go and pushes them out her room.
In the village, Sassette tells Papa about the slumber party and asks if she could go. Papa declines, saying being around Balthazar is dangerous for every Smurf, especially little Smurfs like her. Sassette walks away sad, saying she could do anything if she was an adult.
In Balthazar's castle, Gargamel and Azrael are entrusted to babysit Denisa, as she is having a party, but he has to go out to gather the final part of his latest invention: the futura crystal. Gargamel says his invention is in good hands with him. Balthazar threatens him in case something happens as he shocks Gargamel and Azrael as a head start.
In the village again, Sassette prepares to go to Denisa's party despite Papa Smurf's orders, but she does not want to disappoint her big girlfriend either. She heads off as she hides her disappearance with a decoy in her bed and Smurfy Lou on her pillow.
In the castle, Denisa and Gargamel open the door, revealing the Grackle sisters and their mom. Denisa says she thought they didn't want to play with a little girl like her, so the sisters' mom lies and says they are excited to play with her. Denisa takes the Grackle sisters and shows them around the castle, much to Gargamel's concern.
First, she shows them Balthazar's laboratory. As one of them asks what the "ugly rock" is for, Denisa says it's one of his biggest creations. Then, she shows up with some cookies as they snag it from the plate and sloppily eat it. They are now more concerned with the creation and want to look at it some more, but Gargamel runs and tries to keep them away, worrying they will break it, but he trips and falls as one of the sisters catches it. The girl with the crystal throws it to another sister and that sister throws it to the third sister, who is too short to catch and Gargamel and Azrael catch it, but only when they fall. Denisa is oblivious to the ongoing situation and believes Gargamel is a hit with her new "friends". Gargamel tells her that if the crystal breaks, it's over for him. The sister laughs and ask for more cookies, but Gargamel drags them out of the room.
Sassette now shows up near the window and asks Denisa if she started the party without her. Denisa tells her "friends" showed up after all. Sassette is happy and she can't wait to meet them, but Denisa says the Grackle sisters believe she is a "big girl", and she wouldn't know what they'd think if they see that she is friends with a Smurfling. Sassette understands (at least she thinks) and Denisa says she has to get back to her new "friends" and walks off. Sassette is now mad and wants to see what is so special about these "new friends".
In the village, Papa, Smurfette, and the other three Smurflings are at the Smurflings' playhouse with a piece of cake (from Greedy) as an apology for not being able to go to Denisa's party. But as he takes the blanket off Sassette's bed, Papa sees that the little Smurfling disobeyed him and went to Balthizar's castle, and they all must go at once.
Meanwhile in the castle, Sassette observes Denisa's new friends as they are seemingly playing with her toys. However, they are really taking them for themselves. Denisa comes in and asks what they are doing with her toys, so one sister says it's the "Grackle Grab". Denisa is curious on how this is played, and the sisters simply say it involves taking all of her toys and never giving them back. Denisa is heartbroken, saying she thought they were friends, and friends don't steal friends' toys. One of the sisters says, "Who would wanna be friends with a little girl like you?". Denisa says someone really special, like her friend Sassette. The little Smurfling is happy to hear this while the sisters continue dumping the toys into the bag, Denisa tries to save them, but two of them take her to her swing set, the only thing left, and swing it so hard as she spins. The sisters are about to leave the castle waving, but Sassette jumps in and says they can't do that to her best friend. The Grackle sisters don't care and put her into the bag as well. Denisa spins off the swing set, but she falls out the window and grabs a tree, where a water dragon lives as it prepares for its next meal: Denisa!
Sassette is still captured in the bag and wants to get out, to no avail. Just then, they see a knight ghost who is the "keeper of the castle", scaring the three sisters out of the castle, dropping all three bags. It is revealed that this ghost is none other than Papa Smurf, along with Smurfette and the three Smurflings, with Snappy saying they gave the three big girls a big scare. Sassette comes from the bag and wonders what they are doing and Slouchy says they thought she might need a foot... or a hand.
They then hear Denisa as she yells for help. As they see the danger, Sassette throws a rope, but she can't reach it. She tries harder, but just then, Gargamel and Azrael come and chase the Smurfs, but Sassette stays to save Denisa from the dragon. Just then, Sassette is taken while the running Smurfs duck as Azrael gets caught in the swing set. Gargamel is about to grab all of the Smurfs, but Denisa tells him to "Leave themALONE!!!!", loudly, causing the crystal to almost break as Gargamel catches it. To make matters worse, Balthazar comes in and Gargamel tells him that the crystal is fine... until Azrael bounces into him after getting released from the swing set. The crystal shatters, angering Lord Balthazar to the max and starts zapping Gargamel and Azrael out the castle.
Later, Denisa thanks Sassette for saving her and asks how she could ever forgive her. Sassette says she can forgive her if the other Smurfs forgive her for being "such a fool" and they do. Papa also forgives her, saying she learned a very valuable lesson. Snappy asks if she doesn't mind being a little Smurfling anymore, and Sassette says she has. She also adds that she and Denisa will get to enjoy everything while they're little. As Snappy and Slouchy hug her, she says to Papa that this is what she calls a happy ending.
Trivia[]
The sisters are collectively referred to as the "Grackle Sisters". Grackles are large birds that travel in flocks, bully smaller birds, and monopolize bird feeders. They are considered a pest.
This episode does not feature any background Smurfs.
This is the only Season 8 episode in which Gargamel appears without Scruple.
