Robert, Lily, and Lily's mechanimal wind-up fox, Malkin, have been living together since the adventures that killed Robert's father and revealed Lily's mechanical heart (Cogheart, 2018).Lily is practically Robert's family, and he has nearly settled down to that reality, but how can he completely when there are so many questions about his own life? Where is his mother, Selena, who vanished when Robert was just a baby? Why is vicious escapologist and diamond thief Jack Door on the lam from prison, lurking around the ruins of Robert's old home? Why is Jack so interested in Selena? Perhaps Robert can find some answers in a half-moon locket he discovers, a portrait of his mother within and odd letters engraved on the moon's face. Lily is always happy to help, especially if it means dangerous adventuring aboard zeppelins with inadequate adult supervision. There are plenty of cinematic adventures in this seemingly all-white Victorian England (including a death-defying drop from the skies and a well-paced sewage flood), and there's enough information for readers to decrypt some of the codes. With lots of thrilling dashing about, fleeing from blackguards, and enjoyable wordplay, this should satisfy genre fans.You know it's a "tockingly" good steampunk mystery when the dastardly escaped criminals who stole from Queen Victoria are somehow connected to the hero's mysterious, long-lost mother. (glossary) (Fantasy. 10-13)