Where can I find the grave keepers treasure?

Pull the tombstone that is nearest to the magic bean platform (if you planted it as a child). It's to the left side of the graveyard if you're playing the Regular Quest, otherwise it's to the right side of the graveyard. I has flowers in front of it.

I posted this on another question as well, but the same routine applies.

As adult link go to the Kakariko graveyard.
Once there you will have to go to the grave on the left.
There should be a soft soil patch (or a flower if you planted a bean as young link).
The grave next to the soil patch is the one you should enter.
Pull it back to reveal a hole and jump into the hole.

Once inside you will see dampe, only this time he is a ghost.
Walk up to him and talk to him and he will challenge you to a little race.

Basically it's very simple, follow the ghost of Dampe and don't let yourself fall behind.

You will need to follow the Purple and red flames, ghost noises and the doors inside the grave.
Don't go towards rupees and try not to run into enemies.

I won't tell you the path that you need to walk, because that would take the fun out of it.
Good luck though!

You have to go to Kakariko Village graveyard and go up the first set of stairs, then up the set of stairs to your character's left, then pull the first gravestone to the right back to reveal a hole. Drop down into this hole and go forward. Dampe will stop you and challenge you to keep up with him all the way through his grave to the end. Either way, you will have to keep up with him. Run after him, avoiding the fires he drops, as these can take either a quarter or half of a heart of health away. Follow him to the end. Make sure that when you hear the timer sound, you hurry your ass up to get past the stone door. When you get the treasure, go up the stair case behind the chest and you'll end up in the windmill in Kakariko Village.

By the way you realize iits the hookshot right?

There will be two gravestones that have flowers on it, pull them, in one there is a treasure chest and in the other there is Dampe's ghost. Go in the one with Dampre's ghost and you'll find the treasure(Hookshot).

As adult link go to the kakariko graveyard. Notice how their is a tombstone that was not there when you were a kid. Pull it back and jump in the hole, inside the hole you will see dampe's ghost. If you keep up with the ghost he will give you the gravekeepers treasure A.K.A the hookshot