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 reach a snow-covered land, which causes Yuna to reminisce about her days as a Saint apprentice and her mentor, the kind Peacock Pavlin. Sensing her mentor near, Yuna rushes to her encounter, only to realize Pavlin's allegiance is to Mars. Disciple and master engage in a fierce duel, later Yuna realizes it was Pavlin testing her, as her mentor reveals she is truly loyal to Athena Saori, and informs Yuna she is still alive and being held hostage by Mars. As Yuna prepares to rejoin her fellow Bronze Saints, both female Saints are surrounded by traitorous Silver Saints. Pavlin stays behind to cover Yuna's escape, seemingly losing her life.

Haruto, accompanied by Ryuhou, journeys to his home village in an attempt to come to terms with his past and regain his resolve. While there, Ryuhou learns that Haruto became a saint in order to follow the footsteps of his good friend and older brother figure Yoshitomi, the previous Wolf Saint. Yoshitomi had apparently been murdered by a masked silver saint in front of Haruto and the boy had been desperate for answers ever since. Haruto's fater, despite his disapproval of Haruto becoming a saint, helps him gain back his fighting spirit by staging an assassination attempt on his son's life.

Souma and Sonia are entrapped in an illusion of their past when Souma's father Southern Cross Kazuma was alive. Sonia is revealed to have been ordered by Medea to kill the Silver Saint for he was an open leader against the Martians. Hesitant on her mission she departs and faces Kazuma, as Souma also witnesses the past event. Sonia is first easily pushed away by Kazuma who tells her that her fists are made to protect those she care for, but when she thinks of her family, Sonia bursts into a rage and stabs Kazuma from the back. It is revealed then that after the murder,...

Dragon Ryuhou arrives to the Temple of the Twins, being greeted by a strange, peaceful atmosphere and talking animals. Gemini Paradox, the guardian of the temple, gently welcomes the young Saint and exposes to him her motives for her allegiance to Mars, and reminisces about her past. Disagreeing with Paradox's amoral perspective, Ryuhou engages her in battle, managing to overpower the gentle Paradox. Much to his surprise, she emerges full of hate and with no trace of her previous loving personality. Meanwhile, Aquila Yuna arrives to the Cancer Temple.

Upon arriving at the next temple, Haruto and Souma are confronted by Virgo Fudo, a gold saint whose cosmos surpasses that of all the Gold Saints in the earlier temples. Yuna, Kouga, and Ryuhou join the battle in time to save their friends from a crushing defeat. But even the combined powers of the five Bronze Saints is no match for Fudo. When all hope seems lost, Eden arrive at the last minute and protects them from one of Fudo's techniques.

Eden arrives at the House of Scorpio, watching Souma right next to Sonia's body. Souma apologizes to Eden before moving to catch up with Kouga and Yuna. Meanwhile, Haruto and Ryuuhou awaken at the End of Time, finding themselves confronted by Tokisada, whose time-manipulating powers have regained their strength after his fight against Genbu. From the moment the battle begins, Tokisada easily gains the upper hand against the two Bronze Saints' combined strength. At the same time, Kouga and Yuna reach the House of Sagittarius, supposed to be protected by Seiya. Upon ...

Kouga defeats one of the Heavenly Kings in one hit before he manages to once again keep his Darkness Cosmo due to him having reached his Seventh Sense earlier and Yuna calling out to him. Sending him ahead, Yuna engages Amor while Souma, Ryuuhou and Haruto engage the remaining three Heavenly Kings, using the last bit of strength they have left in order to finally defeat them. Leaving the rest to Kouga, they collapse to exhaustion. Amor decides to fight Yuna, but is interrupted by Eden who has arrived as well. Following a short fight, Yuna asks Eden to go onward and ...

As Earth's Cosmo is transferred to planet Mars, Medea drains the darkness Cosmo from Ludwig's body and transfers it to Amor, before she departs to Mars. After revealing all the suffering and prejudice he has suffered along with his sister during his childhood, Amor attacks Kouga. Eden joins Kouga against him, but when Amor transfers the battlefield to Mars, where his powers are increased to the same level as Mars possessed, Kouga finds on it an opportunity to retrieve Aria's staff and stop Earth's destruction.

Yuna, the only one left standing after Abzu's terrifying onslaught against Kouga's friends, is encouraged by Athena to fight against Abzu in order to bring Kouga back. However, all her attempts fails, gaining her darkness wounds for each attempt. Just then, the fragments of Aria's staff combined with Kouga's friend's Cosmos awaken Seiya, who has been trapped in the depths of the red planet all this time, waiting for a chance to stop Abzu's plans. The Gold Saint confronts Abzu and manages to drive him from Kouga's body with aid from Yuna. The God of Darkness then flees...

With the Gold Saints protecting Athena and the Silver Saints looking for clues about the new enemies, Koga is instructed by Seiya and Saori to assemble the other Bronze Saints. Followed by Subaru, Koga encounters with Souma at the Palaestra, where he is working as a substitute teacher. However, when the Tertiary Pallasite Loge, a master of spear combat appears at the Palaestra, Koga, Souma, and Subaru must work together to protect the students.

Koga and Subaru are sent by Shina to investigate the disappearance of a Silver Saint. Upon finding their missing companion, they are approached by the Secondary Pallasite Europa and the Tertiary Pallasite Thebe and learn, much to their surprise that Eden is now working with them as a Tertiary Pallasite, with the promise of having Aria and the rest of his family revived. With orders to kill Koga, Eden attacks him mercilessly until Thebe decides to intervene and the Orion Saint reveals his true intentions as well as his new Orion Cloth.

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.

Now knowing where Pallas is located, Seiya decides to lead an attack on her stronghold with the intention to kill her. On the way to meet him there, Koga and his friends are ambushed by the Tertiary Pallasite Cyllene and Haruto stays behind to confront him. Subaru decides to assist him ignoring his friends' warning and the two find later that they must fight not only Cyllene but also his twin brother Greip.

The second day of battles begin, and Koga, Ryuhou, Haruto, and Subaru take a chance to make a beeline for the Palace until they are intercepted by Mira, a Pallasite of unknown rank who fights without donning his Chronotector. Despite seemingly at a disadvantage, Mira easily overpowers the party with his speed and his Alchemy Glove's mysterious power to destroy Saint Cloths just by touching them, until Haruto realizes his trick and comes up with a way to fight back, but Mira is barely scathed by the counter. Just as he is about to don his Chronotector, he is ...

Koga and his friends keep traveling in order to find Kiki and fix their Cloths, as only Eden and Subaru can clear a path for the others. They rendezvous with Shaina and Aries Kiki who repairs their Cloths while explaining to each of them what they must focus on the most while fighting. However, Dione appears, and while the legendary Steel Saints Shou, Daichi and Ushio buy some time fending of the Pallasites with the other Saints, Kiki soon arrives to deal with the Secondary Pallasite himself, before Koga and his friends, with reinforced and fixed Cloths, head off ...

At last Koga arrives at the front of Pallas' castle, which is sealed by the "Gate of Time", a massive door reinforced with Titan's powers. Koga attempts to break through the gate by himself but his own life is put in danger instead, until Athena and her Saints arrive to lend a hand.

Tokisada, the former Aquarius Gold Saint who was supposed to be defeated by Haruto at the End of Time, appears before him as a Secondary Pallasite at the second path, donning a Chronotector that enhances his time-control abilities. Haruto, Eden and Subaru have a hard time against him until Hyoga appears to battle him in their place.

After mourning the death of Ikki, Shiryu and Ryuhou have to face off against the Secondary Pallasite Rhea. In the occasion, the Libra Saint takes the opportunity to evaluate how far his son had improved his cosmo.

The young Bronze Saints face off against Gallia on their own, allowing the Gold Saints and Athena to move forward towards Pallas. Although Gallia's Photontector and Bushin Photon Sword seem impervious to harm, Subaru once more calls on the mysterious powerful cosmo to break through Gallia's offensive and actually damage the sword, convincing the others to call upon their own cosmo, transforming their New Cloths into the more powerful Omega Cloths, and together the six Bronze Saints defeat Gallia.

Accompained only by Seiya and Harbinger, Saori finally comes face to face with Pallas. Titan steps in to protect his master and Harbinger challenges the Pallasite, using Athena's cloth to draw his attention. Treating him as a mere ruffian, Titan is surprised by the true might of the Taurus Saint, who proves himself far more powerful and noble than he claims to be.

Sagittarius Seiya faces off against Saturn, the God of Time, and Shun and Hyoga protect Athena and Pallas from Europa and Mira.