New book idea

Okay, this is a new idea for a book that I've got (I'm sorry if my english is bad.. I'm really writing the novel in Norwegian!)

The story is about a 15 year old boy. He lives with his mother, which is a single parent. The boy never knew his father, whom ran out of his mother as soon as she got pregnant. The boy's neighbour, an old, nice man, is however like a father to the boy.

One night he finds his mother dead, killed brutally. An eye witness have seen a big shade in a cloth coming out from the house the same night. The boy gets furious, and decides to hunt down the killer, and make things right.

During the search for the killer, the boy runs into other people. He gets friends, followers, teachers. He learns that the killer is a really bad creature, and that he has to use rare methods to end him. And he learns about magic, sword fighting, love, potions, dragon riding, astrology, and most important: he discovers skills and gifts he didn't knew he had.