1499. Children are disappearing in Venice. Rumor has it a demon is to blame, but no one knows for sure. Beatrice de la Pietà, an orphan on the brink of a new life, cannot be bothered with such stories though. Meeting the expectations of her new employer, Cassandra Fedele, is all she cares about, and she'll do anything to hold onto her new apprenticeship as a cook and maid in her household. Demons and missing children will have to wait.

When Signora Fedele's requirements of Bea take a sharp turn from domestic work to more academic pursuits however, the orphan begins to fear one day she may let the famed scholar down. Matters only become more complicated when Bea meets a girl obsessed with stopping the demon she was so determined to forget. Prompted by her new friend's dedication to justice, and bolstered by the humanistic education she never bargained on receiving, Beatrice reluctantly dives into the danger and daring that flow through the heart of her watery world.