Intriguing start. I am willing to suspend my disbelief and accept your definition of a blue moon as being something differnet in the Wizarding world than in the Muggle one, though it threw me for a minute.
I THINK I read this once before, but I don't remember much about it and I see you have posted a new installment, so I am catching up before reading that.
Sorry, everyone, Chapter three is the third Chapter in the story, but since the first chpter is the prologue, and titled as that, and THEN it says Chpater one, Chpater two as been missed.