Trained from birth in swordplay and combat, a young knight named Siris has journeyed to the Dark Citadel with a single purpose: fight through the army of Titans to face the tyrannical God King in one-on-one combat. This was his father’s sacred mission, and his father’s before him, going back countless generations in an effort to free their people from enslavement.
But when Siris somehow succeeds where all those from his bloodline previously have failed, he finds himself cast into a much larger world, filled with warriors and thieves, ancient feuds and shifting alliances, Deathless immortals and would-be kings. His quest for freedom will take him on an epic journey in search of the mythical figure known as the Worker of Secrets – the one being in the world who can unravel the secrets of the Infinity Blade.
The story picks up from the main ending of Infinity Blade. Siris, the protagonist character in Infinity Blade, returns to his town of Drem's Maw after defeating the God King with the Infinity Blade. The elders of Drem's Maw force Siris to leave because they fear the other Deathless will attack the village to reclaim the Infinity Blade. Siris returns to Lantimor, where he had defeated the God King. While there Siris gains a companion Isa, an assassin who is part revolutionist and part self-serving mercenary. They learn that the God King has been rebirthed and that the Infinity Blade can only permanently kill a Deathless once it has been completely activated. Siris had completely activated the Infinity Blade after defeating Archarin. They travel to the lands of Saydhi, another Deathless, to learn from her where the Worker of Secrets, the creator of the Infinity Blade, is imprisoned so they can return the Infinity Blade to him. Isa remains behind as Siris takes on the champions of Saydhi one by one. Afterward, Saydhi tells Siris where to go, but then attacks him. He kills her, but is captured by the resurrected God King, and the Infinity Blade is retaken by the latter. Isa then kills Siris with a crossbow bolt so the God King cannot kill Siris permanently with the Infinity Blade. Siris then wakes up in a rebirth chamber similar to one beneath the God King's castle, and learns he is a Deathless.