The secret lies with the Heart.

Born with a magical knack for manipulating emotions, Leodora’s only dream is to ensure her talented little sister dances on the biggest, brightest stage in the Republic: The Curiosity, a grand old theater of tradition and innovation. After escaping a cruel carnival, Leo secures her sister a place in the Curiosity’s chorus line, and herself a job as a professional audience member, swaying the crowd’s mood with her magic. The girls have a home for the first time in their lives.

Then a tragic accident darkens the theater. A greedy businessman begins blackmailing Leo, and financial woes threaten to close the show forever. The Curiosity’s sole hope lies in a mythical power source hidden beneath the maze-like passages and trapdoors of the theater—the Heart. And Leo’s only friend Paxton, nephew of the theater’s stagemistress, is the key to finding it.

While Leo and Paxton hunt for the Heart, the blackmailer’s threats loom larger. Mysterious figures, cryptic clues, and deadly traps hinder the search at every turn. If the friends cannot recover the Heart in time, Leo and her sister will be cast out of the only home they’ve ever known, and the final curtain will fall on The Curiosity.