Something is rotten in the kingdom of Hyrule; the evil sorcerer Vaati has stolen the Picorni-blade and it is really important that Link gets it back. You see, Link is a kid and only kids can see the Picorni, which are really tiny folks.
So Link heads out on his quest witch leads him all across the kingdom and into dungeons with terrible monsters. He soon finds a talking hat who assists him and gives him clues on where to go. Also the hat enables him to shrink to Picorni, or if you prefer minish size and get to places where you normally cannot go.
This is what makes "the Minish Cap" different from other Zelda-games, but other then that it plays a lot like "a Link from the Past". Some of the puzzling in between dungeons is very hard and i can imagine people getting stuck in this game and relying on walkthroughs. It seems to me the gameboy advance needed it's own Zelda and thats's why this game was made. When i compare it to "Oracle of Seasons" and "Oracle of Ages", both for the gameboy Color i have to say i liked those games better. These games did not have the nice graphics like "Minish Cap", but the gameplay and story were much more varied, fun and surprising. "Minish Cap" is a Zelda-game by the numbers.
I still recommend it if you are a big Zelda-fan, but it isn't as great as i hoped it would be.