The movie begins with a humorous short featuring SpongeBob, who, along with his friend Squidward, is working a shift at the Krusty Krab. Their typical day takes a comedic turn when Squidward, frustrated with SpongeBob’s constant ringing of the bell to call for orders, accidentally breaks it. Despite SpongeBob's efforts to fix it, Squidward destroys the repaired bell in a fit of irritation, leading to SpongeBob's sadness. In his attempt to entertain himself, SpongeBob ends up with the broken pieces inside his head, causing the ringing to sound from within, prompting Squidward to run out screaming.
The main story then shifts to the Smurfs universe, set in the year 2025. The narration introduces a mystical lore about four Magic Books that balance the universe, which are now threatened by an evil alliance of wizards. These dark wizards intend to harness the power of the books to spread darkness across the world. One of these books, called the Jaunty Grimoire and voiced by Amy Sedaris, manages to escape from the clutches of the villains after a heroic intervention by a trio of Smurfs: Papa Smurf, Ken, and Ron. The sinister wizard Razamel, played by JP Karliak, is determined to retrieve the book and allies himself with a broader evil cabal that includes formidable figures like Chernabog (Nick Kroll), Asmodius (Octavia Spencer), and Jezebeth (Hannah Waddingham).
Meanwhile, in Smurf Village, a lively dance celebration is underway led by Papa Smurf, with Smurfette singing and the other Smurfs—like Brainy, Vanity, Worry, Hefty, and Grouchy—joining in. An unusual Smurf, No-Name, played by James Corden, is desperately searching for his unique identity. Despite his efforts, he struggles to find what makes him special until Jaunty, a mysterious figure, grants him magic powers that initially seem to be his breakthrough.
However, danger strikes when Razamel’s forces locate Smurf Village. They break into the village through a magical portal, capturing Papa Smurf and pulling him into their dimension. Before he disappears, Papa instructs the other Smurfs to find Ken, who has been estranged from his brother Ron and the rest of the Smurfs. The surviving Smurfs, including Smurfette, Gargamel, and new allies, embark on a rescue mission that takes them to the real world and across various dimensions.
The heroes appear in Paris, where they join Moxie, a formidable Smurf leader played by Sandra Oh, in the International Neighborhood Watch Smurfs. Together, they seek out Ken, who has a complicated past with Ron, played by Kurt Russell. Ken agrees to help, and the group ventures through a portal into the Australian outback, where they meet Mama Poot, played by Natasha Lyonne, who helps them understand the evil plans of Razamel and his allies.
Razamel, frustrated with the other evil wizards like Chernabog, focuses on retrieving the Jaunty Grimoire and unleashing chaos. He captures Papa Smurf and threatens to eliminate the Smurfs using a destructive device. No-Name, with his newfound magic, confronts Razamel, revealing that the Jaunty Grimoire is actually a source of dark power, and that he was unknowingly being manipulated. As Razamel taunts and tries to corrupt Smurfette—who was created by villains—she fights back, ultimately grabbing the book to prevent its evil from spreading.
A series of dimension-hopping battles ensue, with No-Name unlocking his true potential and gaining real magical abilities, shaping him into the "Magic Smurf". Meanwhile, Gargamel, played by John Goodman, switches sides temporarily, helping the Smurfs escape Razamel’s lair and fighting against his treacherous brother Razamel’s plans. The conflict escalates to Razamel opening a portal that threatens to destroy everything, but the Smurfs, led by Papa and Ken, rally to confront him.
Finally, Razamel is cast into another dimension after a fierce fight, with the remaining wizards trapped in a cooler. As the dust settles, Ron reappears, alive and well, reuniting with Ken and Papa Smurf. The film concludes with the Smurfs returning to their village, where they celebrate with a joyful dance party. During the credits, Razamel ends up in a dimension where he is toyed with by a giant tardigrade, masterfully played by Jimmy Kimmel, setting up potential future adventures or humorous spin-offs. Meanwhile, Gargamel and Azrael appear in a surprise twist, declaring themselves as new bosses, hinting that their mischievous schemes are far from over.
"Smurfette" sums it up beautifully during the film: > "Sometimes you need to lose everything to find what really matters." This quote encapsulates the journey of identity, friendship, and heroism that runs throughout this animated adventure.