Spoiler Alert: If you haven’t read  Percy Jackson, Heroes of Olympus and Trials of Apollo, you may find it difficult to understand a lot of the references to characters and places as well as some of the mythological references. This review contains spoilers for the earlier books so if you haven’t read them already I would not advise reading this review.

Nico di Angelo, the son of Hades had already been through Tartarus alone and when Percy and Annabeth went, they left the reformed Titan Iapetus, now known as Bob, to die. After Nico hears the universe telling him to listen, and he hears a voice calling out to him for help, he knows that he must go to Tartarus and rescue the person he thinks is Bob. Nico also worries about his boyfriend, Will, the son of Apollo as Tartarus is the worst place for a child of the god of light.

Nico also finds out that some very powerful primordial beings (immortal beings who existed before the gods) do not want his quest to succeed, yet he doesn’t know why. Taking the advice from Percy and Annabeth (their friends and the only other two demigods to survive Tartarus), Will and Nico stick together to survive Tartarus, yet again.

This book is quite woke and progressive and that is something I have seen before in Rick Riordan's writing. This is the first Rick Riordan book that has a queer main character and there is also a non-binary demon, the goddess of nightmares. I did like that this fact is treated as routinely as Percy and Annabeth's relationship.

As far as age appropriateness is concerned, the romance in this book is limited to kissing. Nico, Percy and Annabeth suffer from post traumatic nightmares and Nico shows signs of post traumatic stress.

I loved this book and I definitely recommend it to fans of Percy Jackson. I’m also waiting for the new Percy Jackson book The Chalice of the Gods featuring the original characters from the first series.