"Ponyo" makes no sense at all, which is just how it should be for a Hayao Miyazaki movie. His ethereal films move with the sensible illogic of childhood dreams, and are powerful enough to revert you to the state of a 7-year-old as you watch.
That said, I'm not heads over heels in love with any of his stuff save for "Howl's Moving Castle." His movies tend to enrapture me in the beginning and lose me somewhere in the middle as they follow their hyperactive arcs. At that point I start hanging on for dear life, appreciating what I can and checking my cell phone clock more often than I should.
"Ponyo" was par for the Miyazaki course - loopy, silly and funny in points while still able to knock you over the head with deep human truths. His twisted version of "Finding Nemo" meets "Splash," the movie won't go down as one of his best, but it's still better than 90 percent of animation out there.
Ponyo is a Teletubby-like fish with a human baby face who gets stuck in a piece of trash - as Miyazaki ages he leans more and more environmentalist - and washes ashore, where a 5-year-old boy picks her up and keeps her as a pet. His adoring, supportive mother isn't quite sure whether it's wise to keep Ponyo around, but the boy is in instant love and values Ponyo more than just about everything in his life. The mother probably senses that if she were to take Ponyo away, she'd sever a part of her son's soul.
The kid does all he can to protect Ponyo from an uncaring world, dashing away from kindergarten so he can check on her (he places her in bushes widely just outside school property, subverting the school rule that pets aren't allowed on campus) and fending off interested classmates. But there's no defending against elemental water monsters that crawl out of the ocean, engulf your island in a mini-tsunami and take human-faced magic fishies back home. The boy and Ponyo are parted, heartbreakingly just after Ponyo has finally learned to talk, using her first words to declare her eternal love for the boy.
To explain any more of the plot would only make me sound like a rambling idiot while robbing the movie of its joyfully perilous meanderings, but know that the separation doesn't last long, and soon Ponyo, who proves to have magical powers to transform into a human, make things bigger and heal wounds by licking them, joins the boy on a dangerous journey to find someone both of them love.
Spoiler alert - at the end of the movie, the boy has to vow to always love Ponyo, pretty much agreeing to marry her. I love the way Miyazaki handles this. The boy is understandably a little non-committal about the whole thing, perhaps second-guessing himself after he agrees to the setup by not exactly leaping to symbolically cement the love with a kiss, but Ponyo just sort of steals it from him anyway, and you could swear the boy is suppressing some doubt in the back of his mind. Maybe he's thinking, "Hold up, dude. What if I ever meet another hotter, younger fish-chick? What then?" But by then he's already bought the cow. Such is life in the world of Miyazaki.