The Smurfs 2 movie novelisation - Stacia Deutsch

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.
To save their beloved Smurfette, Papa and the Smurfs return to our world and reunite with Patrick and Grace Winslow. Can they stop Gargamel from learning their secret and ruling the world before it's too late?