Luna Lovegood and The Copied Man

Tom Riddle, age 16, made an astonishing discovery that promised eternal youth and unlimited magical power but needs an intelligent Ravenclaw to raise it to the ultimate level. How might he force Luna to help him enslave the world? And what else will he demand of the young girl? Outrageous twisted mystery in which Luna must surrender her all to save Neville. (Harry's year 6 but AU.)