The concept of Gaara, master of sand, never having made a sand castle in his life is amusing and in all probability correct. I didn't see major grammatical errors, the and flow of the description and dialogue seemed logical, but there was one thing that bothered me about this story: the way Gaara and Temari dismissed water. Coming from a desert, where water is rare and no doubt precious, I have a hard time buying the fact that any of the Sand siblings would write off any amount of fluid as 'just water.'