From the World of Percy Jackson: the Court of the Dead

In 'From the World of Percy Jackson: the Court of the Dead,' demigods Nico di Angelo and Will Solace join forces with Nico's half-sister Hazel Levesque at Camp Jupiter. After inadvertently making the Underworld monsters aware of their options for a different life, the trio must now protect these creatures as a dark force begins to threaten them. With monsters disappearing and connections to their pasts emerging, Nico, Will, and Hazel face a formidable challenge that tests their courage and loyalty.