Good chapter. I hope to see some more interaction between Harry and Sirius, as well as Harry and Voldemort. Concerning Sirius, I think he would choose Harry over Dumbledore, even this colder Harry. Especially since Dumbles didn't use any of his vaunted influence to check if Sirius REALLY was guily! Kinda strange, considering that the old man seem to be a real big believer in second chances and the innate goodness of everyone...
Keep up the good work!!!