When a recent recruit to the new Order of the Black Sun absconds with items from the secret societys vault David Purdue launches a pursuit to reclaim their stolen artifacts and to stop the thief from unearthing a long buried secret of Leonardo Da Vinci With his friend Dr Nina Gould and the Black Suns curator Elijah Dane by his side Purdue embarks on a chase that takes them from the crowded exhibits of the Louvre museum to the very sky itself Pitted against some of the most remarkable inventions Purdue must learn how to overcome Da Vincis most dangerous devices if he has any hope of stopping the thiefs plans Meanwhile Sam Cleave tries his best to protect his friends but his efforts come at a devastating personal cost