Phineas and Ferb the Movie: Across the 2nd Dimension, on Disney Channel
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The movie is set on the five-year anniversary of Phineas and Ferb getting Perry the Platypus as a pet. Meanwhile, Dr. Doofenshmirtz invents an otherdimensionator, but before he can use it, Phineas and Ferb crash into it, after a mishap with their own latest invention. Not realizing he's evil, the boys offer to help him repair the machine. But then Perry shows up to thwart Doofenshmirtz's plan, and the boys learn that he's a secret agent. Phineas is very upset that he's kept this secret from them all these years. Also meanwhile, Cadance decides to start acting more grown up, because Jeremy (who's a year older than her) is starting to look into colleges.
Doofenshmirtz and Perry and the boys end up opening a portal into another dimension with the machine, where they discover that that dimension's version of Doofenshmirtz became the evil dictator of the Tri-State area years ago. The two Doofenshmirtzes become friends (since no one else likes either of them), but eventually the alternate version realizes our dimension's Doofenshmirtz is incompetent, and turns against him. Perry and the boys meet alternate versions of Phineas and Ferb, who know nothing of summer. Later they team up with the Resistance (alternate versions of Candace, Buford, Isabella, and Baljeet- er, I mean Dr. Baljeet) to try to defeat the alternate Doofenshmirtz and to return to the first dimension. Oh yeah, and our Candace got sucked into the other dimension at some point, too. But anyway, after everyone gets back to their own dimension, the alternate Doofenshmirtz invades our dimension with an army of robots, so the good guys have to try to stop him from taking over their Tri-State area as he had his. (I can't help wondering why he doesn't just conquer more of his own dimension instead, but I guess in spite of being brighter in some ways than our Doof, he's still pretty Doof-like in other ways). And meanwhile, Phineas and Perry regain their trust for each other, and in the end, Phineas learns from Major Monogram why Perry had kept the secret. Of course, everyone (except Perry) has to have their memories erased, which I totally knew all along would happen.
Well... the movie, predictably, is extremely self-referential, as well as throwing in tons of pop culture references. It also is reminiscent of some other episodes of the series (not in a self-referential way, more like just repeating old plot ideas). And as always, there are several songs. Also as always, it's incredibly clever and hilarious. There was at least one plot point that didn't make sense to me, though my only real quibble was that we didn't get to see the alternate reality Vanessa Doofenshmirtz. Anyway, I'm leaving out tons of details and spoilers. But the important thing is... it's freakin' awesome.