Return to the beloved world of Percy Jackson and the Olympians in this brand-new adventure featuring fan-favorite demigod boyfriends, Nico di Angelo and Will Solace. Written by #1 best-selling author Rick Riordan and award-winning author Mark Oshiro, this paperback explores a new mystery involving escaped monsters and a dark force connected to the Underworld.

• New adventure set in the world of Percy Jackson and the Olympians.
• Features popular characters Nico di Angelo and Will Solace.
• Co-authored by Rick Riordan and Mark Oshiro.
• Paperback binding suitable for young readers.

Three months after Nico di Angelo and Will Solace returned from Tartarus, they are called to Camp Jupiter by Nico's half-sister, Hazel. Hazel is secretly sheltering a group of monsters who were inspired by Nico and Will to seek alternatives to evil. When these monsters begin to disappear from the camp, Nico, Will, and Hazel discover a dark force at work that is connected to their own past.

• Brand: Puffin
• Author: Mark Oshiro, Rick Riordan
• Binding: Paperback
• Edition: 1st Edition
• Language: English
• Print Length: 448 pages
• Reading Age: 10+ years
• Publication Date: June 18, 2026
• ISBN-10: 0241731429
• ISBN-13: 978-0241731420
• Dimensions: 130 x 197 x 30mm
• Weight: 308g

Dive back into the mythology and high-stakes adventure with this exciting installment focusing on Nico di Angelo and Will Solace's relationship and their role in protecting both mortals and monsters.