Percy Jackson has a really cool concept. The Olympians - who've always fooled around with mortals - haven't grown any more chaste or careful in modern times, so they have lots of demigod offspring running around. Percy discovers he's the son of Poseidon - and what cooler god is there than that? - and has to be indoctrinated into this new world.
Beyond the concept though? It makes no damn sense. See the SPOILER-filled reasons after the break.
I probably won't remember every nonsensical thing that happens in the movie. These are just the ones that still stick with me five days later.
- Zeus' master lightning bolt is stolen and for no stated reason he leaps to the conclusion that Poseidon's son Percy took it. Zeus has always been an impulsive deity, but how about some attempt at explaining why Percy popped into his head? Especially since Zeus is ready to throw Olympus into a war that will destroy the Earth if Percy doesn't return the bolt.
- Percy has been living with his mom and a butthole of a step-father in order to hide him from any Olympians who wish him harm. We later learn though that a) there's a secret camp dedicated to protecting and training the demigods, and b) Percy's already pretty famous amongst the Olympians. Why hasn't Percy been in the camp his whole life with the other kids? I assume there's some explanation offered in the book, but there's not in the movie.
- Percy and his Olympian protector see what they assume is the death of Percy's mom. Two seconds after some pained expressions and an apology, they're laughing and joking and exploring the camp. That's just one example of the lack of emotional honesty most of the characters have in this movie. (Sean Bean and Kevin McKidd as Zeus and Poseidon try especially hard to make it otherwise though. Their actions don't always have logic to them, but the actors really sell that they believe in what they're doing.)
- Chiron (Pierce Brosnan, who also does a great job as a minor, but important character) has a perfectly reasonable plan that has a chance of not only saving the world, but releasing Percy's mom from Hades. It involves Percy's appealing to Zeus in person as an act of good faith and protesting his innocence. Risky, yes, but better than Percy's idea to break into the underworld first to rescue his mom and - while there - to appeal to Hades (because he's always easy to deal with, especially when you're stealing souls from him) to help present his case to Zeus. We're asked to get behind Percy as having the better plan.
- Percy, his protector (a satyr named Grover), and Annabeth (the daughter of Athena, played by Kate from White Collar) sneak out of camp to rescue Percy's mom. Knowing that it's easier to get into Hades than out of it, their plan consists to gathering three, magic pearls that transport you wherever you want to go when crushed. Three rescuers. Three pearls. To help a fourth person escape. You see the problem; the rescuers don't. Not until they get to Hades and it's too late anyway.
- The pearls are all in the possession of (or are being guarded by) modern manifestations of mythological beings. This is for no other reason than to show how clever someone is in making the updates. Medusa (Uma Thurman) runs a road-side statue garden, the Hydra appears as seven janitors at the Parthenon in Nashville until its pearl is threatened, and the Lotus-eaters reside in the Lotus Casino in Las Vegas. There's no explanation for why any of these beings have relocated to their current locations or why they have the pearls or why they haven't been found out and dealt with by human authorities before now. They're merely obstacles to be overcome, and even then, not in any original way.
- Though the heroes have enough foresight to grab Medusa's head after cutting it off, they only use it once against a future threat and then forget about it. They don't discard it, because it shows up at the end of the film, but they don't even try to use it once they get to Hades where you'd think it might come in especially handy. (They also seem very relaxed around it, for such a powerful weapon. One character even kisses it for a supposed laugh. Just another example of the emotional unreality in the film.)
Two out of five tridents.