[7] Timmy Turner (Drake Bell), his fairies (Cosmo, Wanda, and Poof), and Tootie (Daniella Monet) have been traveling around the world granting wishes for others.

However, an elf explains that Timmy cannot be Santa since he is on the naughty list for granting wishes that messed up Santa’s nice list, and Cosmo, Wanda, Poof, and Jorgen cannot change that since Earth's magnetic polarity at the North Pole nullifies fairy magic.

Timmy insists going alone, since this is his problem, however, Tootie, the fairies, two elves, and even Mr. Crocker (who came to get his name off the naughty list) decide to tag along.

The fairies help the others over, however, the still vengeful gingerbread men come, and in an attempt to get Crocker over, Timmy falls down, but manages to clamber back up the cliff using candy canes as ice axes given to him earlier by Santa.

Timmy and the others then take Elmer's vehicle to get back to the workshop, but realize that without Christmas spirit, the evil Winter Warlock (negativity and depression) has covered the whole planet.

The elves explain that Timmy has a very small chance of saving Christmas now that Winter Warlock has blocked the path out of the North Pole.

Timmy quickly puts on Santa's clothing, restoring power to the workshop, and gives orders to everyone else to prepare all the gifts.

Despite not getting off the naughty list, Crocker gets his first-ever Christmas present (a new tie that looks exactly like the one he already has, which he loves) and Timmy and Tootie kiss under the mistletoe.

on Nickelodeon, The Fairly OddParents creator and film writer Butch Hartman tweeted that he was working on ideas for a sequel to Grow Up, Timmy Turner!

[4][5] In 2013, it was announced there would be a third and final installment, titled A Fairly Odd Summer, with Drake Bell and Daniella Monet reprising their roles.