"The Burning Bridge" is the second book in the Ranger's Apprentice series by John Flanagan. It follows the adventures of Will, a young apprentice ranger, and his friend Horace as they face new challenges. They must prevent an impending invasion by the Skandians while uncovering a traitor in their midst. In this installment, Will and Horace embark on a mission to warn their kingdom of the threat. Along the way, they encounter various obstacles, including treacherous landscapes and fierce enemies. The story emphasizes themes of friendship, bravery, and loyalty as they strive to protect their homeland.