Ghost in the Vault - Ghost Night, #5

Caina has made many enemies, and chief among them is Lord Corbould Maraeus, the most powerful noble in the Empire of Nighmar. But the Empire is facing dire peril, and Corbould needs all the allies he can find. If Caina can find a missing ambassador, Corbould is willing to forego his vengeance against Caina. Except no mere political intrigue has snared the missing ambassador. For the ancient evils in the forgotten Vault of the Moroaica are awakening...