The past meet present. And, present meets future. During the Winter Solace, the Olympians have a meeting, with the campers. But, not only is it the Winter Solstice when Percy Jackson is Twelve, but when the Master Bolt and Helm of Darkness are stolen. Find out as Thalia meets past, Percy meets future, and Nico meets...
The Fates feel like the gods and demigods need to know what Percy and Annabeth went through in Tartarus, so they send the demigods and a book called The House of Hades back in time to read with the past gods.
The Seven of the Great Prophecy (minus Percy and Annabeth, they are in Tartarus), plus Nico, Thalia, and Reyna are sent back in time to after Percy's first quest. Craziness is insure as past and present collide. I do not own Percy Jackson.