Some kids learn of a game of hide and seek that takes place in a ruined city. Though they are warned that sometimes kids "disappear" when playing, they all decide to play. One of which, a boy named Hikora, has his own reasons for attempting the game. His sister was one of the kids to go missing...
The opening, descending down into the ruined city, is staggeringly beautiful. Everything else is as stunning. Smooth animation. Clear character detail. The works.
At 25 minutes Kakurenbo does not have enough time to wear out its welcome. It sets up its situation quickly, introduces its characters, and sets things in motion. Some characters aren't as fleshed out as others, but that doesn't matter much in the long run.
The story itself is a trifle obvious, but between the voice acting and the moody visuals this is not a problem. While personal preference suggests that I'd like the subtitled more, the dubbed version I watched was most excellent.
This was broadcast as a special on October 29th on Cartoon Planet. I don't know if it will be played again, but it is well worth seeking out. It is the first film made by YamatoWorks, and I hope more such quality works follow.
UPDATE: I saw Kakurenbo on sale at my local Best Buy, so you might be able to find it at you're local vieo rental place.