Kian Ashborne, a slave in the Kingdom of Athos, defied his fate and trained to become a swordmaster. One day, his master sends him on an unusual quest to retrieve an ancient sword, a legendary weapon that only the Supreme Master can wield. The Supreme Master is said to be the destined overlord of the four kingdoms, possessing extraordinary skill in battle. Kian never returns with the sword. Instead, he shapes his own destiny, establishing a mighty new Kingdom with the help of his friend, Ruma. He becomes the great King of Sylvaris. Years pass, and Kian now has several wives and children. Neptune, the King’s fourth son, is his father's favorite, being the only son of the King’s beloved Consort. However, among his formidable brothers, Neptune seems the least capable. He is weak, slow, and timid. His elder brothers despise him for the affection the King shows him and constantly plot in secret to dispose of him. The kingdom's peace is shattered when the King has a dream that makes him remember the ancient sword. To determine his heir and uncover the truth, King Kian organizes a grand contest to discover which of his sons is the true Supreme Master.