The Burning Bridge by John Flanagan

This collection of excerpts, primarily from a work titled "The Burning Bridge," centers on a perilous mission undertaken by Will, an apprentice Ranger, and his companion Horace, a Battlemaster apprentice. Under the guidance of the more experienced Ranger Gilan, they travel through a dangerous, seemingly deserted Celtica to deliver important dispatches to the King. Along the way, they discover Morgarath, an enemy lord, is using captive Celtic miners to construct a massive bridge across a great chasm, a structure not mentioned in captured enemy plans, which reveals a dangerous deception. Their journey is complicated by encountering and traveling with Evanlyn, a young woman fleeing the Wargals who are enslaving the miners. While the boys and Evanlyn destroy the bridge, Will and Evanlyn are captured by Skandians who are allied with Morgarath, while Horace escapes. The larger conflict focuses on the Araluen army preparing for battle against Morgarath, utilizing a clever ruse based on Halt, another Ranger, defeating a contingent of Skandians. The narrative culminates in a dramatic duel between Horace and Morgarath, and ends with Halt receiving news of Will's capture and vowing to rescue him from the Skandians who are taking him through the fens toward their ships.