The Court of the Dead

After returning from the depths of Tartarus, demigods Nico di Angelo and Will Solace agree to join Nico's half-sister Hazel at Camp Jupiter on the West Coast. She needs their help in managing a situation that the boys inadvertently brought about: the demigods showed the monsters of the Underworld that they have options; they don't have to be evil. Nico and Will are on site, assisting Hazel when one by one monsters start disappearing from camp... 9+