The evil wizard Gargamel has created a group of mischievous Smurf-like creatures called the Naughties to harness the all-powerful, magical Smurf-essence. But when he discovers that only a true blue Smurf can give him what he wants, and only a secret spell that Smurfette knows can turn the Naughties into real Smurfs, Gargamel kidnaps Smurfette and imprisons her in the city of Paris.