"Action-packed and filled with great friendships, terrible villains, plot twists, and plenty of humor."— San Antonio Express-News In the gripping final book in the Riddle in Ruby trilogy, young thief Ruby Teach and her friends must save their city from an evil scientist with nefarious plans. The epic conclusion of the Riddle in Ruby trilogy is a hilarious and dastardly adventure perfect for fans of The School for Good and Evil and The Amulet of Samarkand. In the past year, Ruby Teach was kidnapped, taken to a remote fortress, and experimented on by an evil scientist working for the crown. And even though she's finally been reunited with her friends, her trouble has not ended. The vile Dr. Swedenborg has created a machine that steals the life force out of the unsuspecting citizens of Philadelphi, and Ruby and her crew might be the only ones brave enough to stop him. With a mix of magic, science, friendship, peril, and one adorable mechanical otter, Kent Davis's reimagining of colonial America is wholly original.