How to Steal a Dragon's Sword is the ninth book in Cressida Cowell's How to Train Your Dragon series. The story continues the adventures of the unlikely Viking hero, Hiccup Horrendous Haddock III, and his loyal dragon, Toothless. The plot involves a perilous mission to retrieve a legendary sword, likely from a dangerous dragon or a powerful enemy, testing Hiccup's intelligence and his deep bond with Toothless. The narrative is an action-packed quest that explores themes of heroism and destiny.