Faith's father is a clergyman, a traveler, and an antiquarian. Faith adores her father, and he entrusts her with his secret research. He takes her with him to a cave, where he plants in the ground a tree brought from afar. It is the Lie Tree. The next day her father dies, and Faith must find out whether it was suicide or murder after all. Faith will have to play a game and “make a deal” with the Lie Tree. And this is how it works: you must whisper some lie to its leaves. Then you must make as many people as possible believe that lie. The more people believe it, the larger the fruit that grows on the branches of the Lie Tree. Then you can eat this fruit and learn some truth proportionate to the lie you whispered.
Faith must discover what incredible lie her father invented as he prepared to learn a grand truth from the fruits of the Lie Tree.