Avril Diggory and the Memory of Tom Riddle

Avril returns to Hogwarts for her second year, her usually outgoing self reserved despite assurances that her friends and 'brother' wouldn't leave her. But then a voice joins her in her head, she skips classes, gets amnesia, Harry finds a diary and muggleborns are petrified here there and everywhere. And only one thing's for sure, she's the one trying to kill them all.