The Smurfs get ready for the Blue Moon Festival. In his home, Papa Smurf sees a vision of the Smurfs in cages, Clumsy Smurf holding a dragon wand, and Gargamel being powerful. He decides to suspend Clumsy from picking Smurf Roots, but Clumsy secretly does so anyway. However, Gargamel sees him and follows him into the village. The Smurfs all flee, and Clumsy runs into a forbidden cave. Papa,Smurfette, Grouchy, Brainy and Gutsy notice this and hurry after him. They find him at the edge of a cliff, and while trying to help him up, they are sucked into a gigantic vortex, leading to New York. Patrick and Grace, a married and expectant couple, befriend them and allow them to stay in their apartment.
Papa learns that he will be able to get them all home in a couple nights. But first, he must figure out the spell to do so. Patrick tells them that there is an old book store in the city, and they head there to get a spell book. After lots of searching, they find one of their own comic books, containing the spell. Gargamel hears where they are, so he sneaks into the book store and finds a dragon wand, which he then steals. He uses the dragon wand to abduct Papa. The Smurfs promise Papa that they won't try to save him. However, Clumsy stayed behind, so he plans a rescue, along with Patrick. The other Smurfs agree to help. Meanwhile, Gargamel is going to remove the "Smurf essence" from Papa and charge it into the dragon wand, which would make him more powerful than anything else in the world.
Patrick and the Smurfs battle Gargamel while Smurfette saves Papa. Also, Brainy reads the spell and opens up the portal, allowing him to go home and round up his friends. They, too, join the fight. Gargamel captures Papa again and throws him into the air, but Patrick catches him. Right before Gargamel can destroy them both, Gutsy knocks the dragon wand out of his hand. Clumsy tries to catch it, and Papa believes that he will fail, but, much to Papa's surprise, he manages to catch it. Without his dragon wand, Gargamel is powerless, and Papa destroys the wand once and for all, and the Smurfs return home. Patrick and Grace have a baby boy, whom they name Blue, and the Smurfs rebuild their houses to look like what humans have.
