Emily is contending with great changes, including diminished powers, but goes to London to rescue Agent B and others from the CRU, where she makes horrible discoveries about the agency's history.

Nico, the son of Hades, and his boyfriend Will, the son of Apollo, travel to Tartarus, the deepest, darkest part of the Underworld as they attempt to rescue an old friend. As the son of Hades, Nico di Angelo has been through so much, from the premature deaths of his mother and sister, to being outed against his will, to losing his friend Jason during the trials of Apollo. But there is a ray of sunshine in his life-literally: his boyfriend, Will Solace,...