Karn Korlundsson is a gamer. Not a riddle solver. But in order to rescue his best friend, Thianna Frostborn, he will need to travel to the faraway city of Castlebriar (by wyvern), learn how to play a new board game called Charioteers (not a problem), decipher the Riddle of the Horn, and tangle with mysterious elves.
- ISBN: 9780385390361
- Author: Anders, Lou
- Illustrator: Gerard, Justin
- Published: 2015 , Crown Publishers
- Themes: Adventures, Dragons, Games
- Descriptors: Fantasy, Fiction, Intermediate (ages 9-14), Myths and Legends, Nordic
- No. of pages: 352