The Lie Tree by Frances Hardinge
Published in the UK by Macmillan, May 2015; in the US by Amulet Books, April 2016
Faith Sunderly leads a double life. To most people, she is reliable, dull, trustworthy—a proper young lady who knows her place as inferior to men. But inside, Faith is full of questions and curiosity, and she cannot resist mysteries: an unattended envelope, an unlocked door. She knows secrets no one suspects her of knowing. She knows that her family moved to the close-knit island of Vane because her famous scientist father was fleeing a reputation-destroying scandal. And she knows, when her father is discovered dead shortly thereafter, that he was murdered.
In pursuit of justice and revenge, Faith hunts through her father’s possessions and discovers a strange tree. The tree bears fruit only when she whispers a lie to it. The fruit of the tree, when eaten, delivers a hidden truth. The tree might hold the key to her father’s murder—or it may lure the murderer directly to Faith herself.