Ryūhō, the son of the legendary Bronze Saint Dragon Shiryū returns to the Palaestra after a short absence. The young Saint apprentices are subjected to a strict training to master their Cosmo element. Kōga is later forced to battle Ryūhō in an intense element-to-element duel.

The malevolent entity known as Mars invades Sanctuary, accompanied by Capricorn Ionia and the young girl they claim to be the new Athena. Mars then completely obliterates the millenia-old Sanctuary, replacing it with his very own fortress. Meanwhile, Kōga manages to escape the Saint Prison with the help of Wolf Haruto, and after rejoining the other Bronze Saints, they set off together to invade Mars' headquarters, to rescue the young girl and to learn about the whereabouts of the true Athena

The Bronze Saints arrive to a desert area, in which they meet a young girl from the people of Jamir, called Raki, who at first attacks them. After realizing they are Saints, by tradition connected to the people of Jamir, Raki takes them through a shortcut to avoid the desert areas, only to be greeted by the challenge of Kerberos Dorie, who seeks to capture Aria. Managing to defeat Dorie after a difficult battle, the Bronze Saints resume their journey, bidding farewell to their young benefactor, who later is joined by her mentor, Appendix Kiki, the former apprentice of the legendary Aries Mu, now a young man, who realizes the Bronze Saints are the new embodiment of hope in this era.

Learning of Souma's defeat, Eden leaves the Sanctuary in order to find Aria himself. He eventually manages to track down Aria, who is accompanied by Kouga and Yuna. After easily defeating Yuna, Eden and Kouga have their long awaited fight. However, the Orion Bronze Saint easily dominates the battle despite Kouga's best efforts. Not wanting to see her friend hurt, Aria allows Eden to take her away.

After leaving Eden, Mycenae returns to guard his House, where Haruto and Souma arrive promptly. The young Saints find themselves to fight their way through the House of Leo, but the ferocious Mycenae proves to be an almost impossible foe to overcome, even when the two teenagers fight him together and neutralize his King's Roar technique. When he unleash his King's Emblem, Haruto risks his life by stopping Mycenae's final attack. Souma retaliates with a Lionet Bomber powerful enough to crack one of the shoulder pads on his Gold Cloth. The fierce determination of the ...

Kouga finally reaches Mars' location, determined to stop him. As the War God deflects his attacks and counterattacks, Eden arrives in time to save Kouga. Mars then reveals to the true story from the days when he was known as Ludwig, a normal human who sought revenge for the death of his beloved wife, Misha. He deflects Eden's attacks before removing his mask, revealing himself as a human no longer.

The Steel Saints training facility is stormed by the Pallasites led by Hati. Koga and Subaru arrive soon after and they learn that the residents had previously evacuated with former Bronze Saints Ban and Nachi. While investigating, Koga learns about Subaru's origins from his fellow Steel Saint Erna, and it is revealed that among the Steel Saints, Subaru has the strongest Cosmo, and that one day he may find his own Guardian Constelation and become a proper Saint.

Koga, Yuna, and Souma advance through the first path while Shun stays behind to deal with the enemy reinforcements. However, the Secondary Pallasite Surtr blocks their path enveloped in a defensive barrier that seems impenetrable, until Shun catches up with them and realizes the secret behind the enemy's trick.

After dealing with Paradox, Gallia turns her attention to Athena and the Gold Saints, easily deflecting all their attacks until she reveals her Photontector. Meanwhile, the other three groups figure out the meaning of their endless running, figuring out that someone has put them into an endless corridor. As Seiya's attacks are easily deflected, and Gallia is about to kill him, Pallas informs her to stand back, with Gallia mocking Pallas for receiving no love in spite of being the Goddess of Love. However, Integra and Paradox combine their Cosmo, and destroy Europa's ...

After donning his New Gold Cloth, Seiya battles Titan, who questions his loyalty to Athena and the Sagittarius Saint reveals that his drive to follow Saori comes from his feelings for her. Knowing how he feels out of his devotion to Pallas, the Pallasite attacks with all his Cosmo, just to be wounded by Seiya's arrow. Pallas intervenes to protect Titan and Saori then reconciles with her, seeing how she has reformed after assuming her love for him. However, Europa appears and uses the curse laid on the goddesses to drain their Cosmo and pours it on Subaru, who is ...