Hawaii before Western contact was a land of near-constant warfare, and the Koa were its elite fighting caste, trained in Lua, a martial art built around breaking bones and dislocating joints at close range. This History Hit episode traces how Hawaiian society organized around chiefs, tribute, and combat, and how the Koa's discipline and hierarchy made them formidable defenders of their islands. The film builds toward the death of Captain James Cook at Kealakekua Bay in 1779, laying out the misunderstandings, ritual expectations, and escalating violence that turned a friendly landing into a fatal confrontation. Historians and martial arts experts appear on camera to explain Lua's techniques and its role in Hawaiian military culture, while location filming and reenactment-style sequences illustrate how Koa warriors fought and how Cook's crew were overwhelmed on the beach. The episode treats Cook's death not as a simple ambush but as the collision of two incompatible systems of meaning, one of them backed by warriors trained since childhood to kill efficiently.