Frozen: Anna & Elsa: The Great Ice Engine (Disney Chapter Book (ebook))

Oaken presents Anna and Elsa with his newest invention - a strange-looking contraption designed to harvest ice! Kristoff and the other ice harvesters challenge Oaken and his machine to a friendly contest. But the next day, the engine and the harvesters have gone missing! It's up to Anna, Elsa, and Olaf to find them.