The story is as follows: as usual, Link is just an average guy going about his life and being just a little bit hopeless, but before long, disaster strikes. A man named Yuga appears, turns a woman named Seres into a painting and escapes into a portal. Link soon discovers that he must collect the Pendants of Virtue in order to get the Master Sword and defeat Yuga. It does sound like a very generic Zelda story, but things actually take a very interesting and unexpected turn later on, but I won't go into that as I don't want to spoil anything.
Aside from the usual elements of Zelda games (a big beautiful world to explore, secrets to find, dungeons to get through, bosses to beat) this game adds one or two nice new features. First, there are item rentals. All of the items required to get through all of the dungeons are available from the start in a shop run by an entertaining new character called Ravio. You can either rent them for a cheap easily affordable price, or actually buy them for quite a bit more. The difference is that if you have only rented an item, Ravio gets it back when you die, and if you own an item you always keep it and have the option of updating. This means, if you rented all your items, dying would lose you everything. While this does make dying have much bigger consequences than usual, it also doesn't really matter, since the game is a little too easy and you'll probably not die much (I never did).
The 3DS's StreetPass feature is also integrated into gameplay. You design your own version of Shadow Link and then people you pass on the streets can find him on their map and fight him. It's a nice little feature, but, it's not really anything special. You get money from these battles, but I wish you got something more useful.
Shortly into the game, Link also gets the ability to merge into walls as a painting which means, for example, he can slip through a crack in the wall to get to another room. I really love this feature because it's extremely well used and it makes this game very different to the other top down Zelda games. In fact, I got so used to it, than when playing similar games later, I'd occasionally think the solution to puzzles involved wall merging.
For me, this is one of the best Zelda games. The soundtrack is magnificent, there's a lovely mix of old and new, there's a nice amount of side quests to do and it's all so open, too. You can pretty much do things in any order you feel like. Other than, perhaps, the first, very few other games in the series have this much freedom and it feels very good. There are a couple of little downsides, like the return of the annoying save points from Skyward Sword and the fact that it's a little too easy, but still, this is one of the best and is certainly not to be missed!