So it's Christmas Eve, and Phineas and Ferb realize that while they give letters to Santa, they never do anything for Santa himself. So with that, the boys try to persuade the entire town to make a giant thank-you for Santa Claus, and the boys also make a rest stop for Santa. Meanwhile, Candace wants to give Jeremy the perfect Christmas gift. However, after Dr. Doofenschmirtz's Naughtyinator makes Santa believe that all of Danville has turned naughty, Phineas decides to show Santa that Danville is a nice city.
I'm going to talk briefly about the Candace plot, since it was only about 7 minutes long. Really, it was boring, and her explaining the metaphors she says, wasn't really that funny. However, the end with the Gift of the Magi parody was cute, but wasn't hilarious.
I love how at first Doofenschmirtz sings a song how he doesn't hate Christmas, like all the other villains, but all he wants in life is to hate Christmas. That's a nice twist to the cliche, and was very funny. And the reason he used the Naughtyinator was because carolers begged for figgy pudding, and wouldn't leave until they got some, however, it was just part of the song they were singing. That was hilarious!
Anyway, Phineas records a song with Danville to persuade Santa that the town is nice. So two elves come over and talk about the problem. However, Doofenschmirtz's Naughtyinator gets destroyed by a strong note sung on a CD Perry got from a Secret Santa. So now, everyone is nice again. But, Santa already left, so Phineas and his friends decide to save Christmas and give all the gifts of the town before Christmas Day. Meanwhile, this Naughtyinator was actually given to Doofenschmirtz by Santa Claus, who was the singer on the CD who broke the Naughtyinator. And, it just so happens that Santa did this whole story just to pull a little prank. That's not a great twist.
Overall, it does have some clever story-lines, a few memorable songs, and some really funny jokes. However, there are a lot of boring parts, and isn't really as memorable as other Christmas specials like the Fairly OddParents. I'll give it an 8.5 out of 10.