The Bronze Knights have defeated the Master of Sanctuary and restored Athena to the helm of Knighthood. Now their adventure truly begins! Gods now walk the earth in human form, and not all of them are benevolent. Princess Sienna discovers this when she meets Julian Solo, who claims to be Poseidon, god of the seas. Julian believes that Sienna, the incarnation of the goddess Athena, is destined to be his bride. And his plans for their future together include a world cleansed of the human race...

To save the world from Poseidon's wrath, Athena makes a grim bargain, sacrificing herself for the good of humanity. Now only the purest of heroes can save her life and stop Poseidon from flooding the world. Seiya, Hyôga, Shiryû, Ikki and Shun must once again don their Cloths and fight in Athena's name!