The story takes place 1,500 years ago, when Vortigern (Jude Law) betrayed his brother King Uther (Eric Bana), breaking the balance between humans and wizards that had been maintained for a hundred years. Fortunately, King Uther's only descendant escaped, which prevented his bloodline from being cut off. In a blink of an eye, 15 years later, the little baby was named Arthur (Charlie Hunnam), who grew up at the bottom of society and knew nothing about his life experience. After killing his brother, Vortigern took over power and exerted his iron-fisted rule, and people were living in misery for a while. By chance, Arthur pulled out a sword deeply inserted into the boulder. According to legend, only people with royal blood can lift this sword. The news soon reached Vortigern's ears, and Arthur was arrested.