Scarlet and Ivy: The Lost twin by Sophie Cleverly (#1 in the Scarlet and Ivy Series)
"This is the story of how I became my sister..."
Early in the 1920's Scarlet, sister of Ivy died in an unfortunate accident. Miss Fox of Rockwood girls boarding school just couldn't let the school be known to be unlucky. So she gets Scarlet's sister Ivy to pretend to be her dead sister. That can't be too hard, right? Wrong! Ivy and Scarlet's personality were completely opposite and the diary that belonged to Scarlet has some unusual entries in them and Ivy has to solve the mystery while still acting like her sister... Author: Sophie Cleverly Publisher: HarperCollins (2015) Genre: Realistic Fiction