The weakest profession, capable only of purifying souls, is actually the strongest ability that can grant the power of Heroic Spirits!? Luke, a "Medium" belonging to a Hero's party. He purified ghosts by conversing with them and cleansing their souls, but was expelled with the remark, "Don't dawdle with monsters." While wandering through a dungeon in despair... he finds a girl being attacked by an Undead Knight! Luke had aimed to become a Medium who could protect both people and spirits, following his grandmother's teachings. When he rushed out regardless of the danger——the "Heroic Spirits" sleeping in the dungeon responded——! Luke gains the power of blue flames!! The Sword God who stopped the monster invasion, the Pirate Queen who protected a castle from a dictatorial nation—— Lodging the powers of Heroic Spirits with extraordinary abilities, the adventure to become the strongest Medium begins!!