Where the Line Blurs

It's the middle of sixth year, and Harry has been suspicious of what Draco has been up to. Draco, is confused. For once in his life, he isn't sure what the right path is. It should be easy, kill off Dumbledore and finally win his father's respect. So why does it seem so wrong? So what happens when Draco finds that he is on the wrong side of the war?