After Jack becomes apprenticed to a Druid bard, he and his little sister Lucy are captured by Viking Berserkers and taken to the home of King Ivar the Boneless and his half-troll queen, leading Jack to undertake a vital quest to Jotunheim, home of the trolls.
Jack y su hermana, Lucy, son capturados por los Nórdicos Berserkers y llevados a la casa del Rey Iva el Sin Hueso y su reina. Para sobrevivir Jack debería viajarse al mundo de los duendes.