The Sun and The Star by Rick Riordan and Mark Oshiro

First off, stop reading if you haven’t read the other Riordanverse books. Still here? Okay, cool. This is the best! Following the events of The Trials Of Apollo series, Nico Di Angelo and his boyfriend Will Solace are alone at Camp Half-Blood, and they’re happy. There’s only one problem: Nico keeps hearing someone calling for help…from Tartarus. It could only be Bob, the reformed Titan. So Nico and Will set off on a quest. But Tartarus is a dangerous place, especially for Will, a son of Apollo. Can the two make it through the most dangerous place in the universe without losing their minds? There’s so much queer joy, Greek mythology, and it’s just such a good book. It doesn’t hurt that queer joy and Greek mythology are two of my favorite things! Everyone should read this. After they read the other Riordanverse books.