Hint: Zugzwang.

Very tricky puzzle... can you guys solve it? 

The knight on d4 is BEAST

heehee!

Don't read this comment until you solve the puzzle! :3

And don't read the column on the right either until...oops, never mind.

I think this is an ending to a famous Reti study. Very nice.

There was no need for 3. Kxh2. He loses nevertheless.

3. Kxh2 is a blunder, since black would reply 3... Bf4+ and then play 4... Bb8. Apart from that Azkadaz did a nice job by showing all these variations. On the third move white should leave his king on h1 and play 3. a7 and get a queen next move.

NO i didn't get it   GREAT PUZZLE !!

Gah!   It annoys me when people only post the finish of a beautiful study instead of posting the setup as well.  It's like posting Rd8# without the rest of the game for Morphy's Opera game... a study is a work of art and you don't do it justice if you deliberately leave it incomplete.  For anyone who cares, the study in question was composed by Reti in 1922 - here is the full study.