Petunia performs a bit of accidental magic. It says something about her parenting that Uchiha Itachi is considered a better prospect for raising a child. Young Hari is raised by one of the most infamous nukenin of all time and a cadre of "Uncles" whose cumulative effect is very . . . prominent. And someone had the bright idea to bring him back to England. Merlin help them all.

Dark curses don't play nice- not even with each other. When nine year-old Harry is bitten by a werewolf, the horcrux fights back. The result could only happen to Harry Potter. Canon-ish for the first three years of Hogwarts - AU from that point forward.