One year after the defeat of Abzu, peace has returned to the world. However, a new threat rises with the advent of Pallas, an old enemy of Athena. Despite knowing that, Seiya can't find the resolve to kill the young Pallas as she is still an innocent child although she is destined to eventually come after Saori's life. Meanwhile, Kouga, training while still recuperating after his battle against Abzu, meets Subaru, a Steel Saint who is eager to challenge him in order to become a God. However, Kouga refuses to fight him and claims that with the world in peace and his ...

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.

Souma, Koga, and Subaru travel to meet Kiki and Raki in order to have Souma's cloth fixed. Yuna arrives there first, but upon having her cloth restored, she finds herself unable to use it and Kiki claims that it is due to her indecision that is wavering her Cosmo. However, when Raki is attacked by two Tertiary Pallasites, Yuna finally gains the resolve to awaken her new Aquila Cloth and fight once more as the Aquila Saint with the help of Souma in his new Lionet Cloth.

Unaware of the advent of the Pallasites, Ryuhou believes that there is no reason to fight anymore and wants to return the Dragon Cloth to his father Shiryu, whose senses were restored, and live peacefully with his family. Meanwhile, Koga and the others learn that a Pallasite is after Ryuhou and rush to assist him, but when Ryuhou finds himself struggling to protect his mother Shunrei from the enemy, his renewed determination awakens his true power as the Dragon Saint and the new Dragon Cloth.

With Yuna, Souma, and Ryuhou leaving ahead to the Sanctuary, Koga and Subaru look for Haruto in Japan and find, much to their surprise, that he is now a singer in a rock band. Haruto rejects Koga's pleas to return, claiming that to him, his music is now more important than being a Saint. However, during a concert, Haruto watches Koga and Subaru being attacked by some Pallasites, and to protect his friends and his fans, he dons his brand new Wolf Cloth to join the battle.

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.

Ryuhou, Souma, and Yuna arrive to a village whose survivors of the Pallasite Halimede's attack are under Shun's protection. Among them is Ray, a child whose brother was also frozen by Halimede and blames Shun for it. Halimede instructs Ray to steal the Andromeda Cloth Stone from Shun with the promise of having his brother return to normal, but when the enemy intends to kill both, Shun brings the power of his cloth to the next level.

Ryuhou, Souma, and Yuna arrive to a village whose survivors of the Pallasite Halimede's attack are under Shun's protection. Among them is Ray, a child whose brother was also frozen by Halimede and blames Shun for it. Halimede instructs Ray to steal the Andromeda Cloth Stone from Shun with the promise of having his brother return to normal, but when the enemy intends to kill both, Shun brings the power of his cloth to the next level.

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 and Subaru return to the Palaestra which is full of refugees from the villages attacked by the Pallasites and rendezvous with their friends. Genbu approaches the Bronze Saints and, noticing how much their cloths are damaged, reprimands them for relying too much on them instead of their own abilities. When a large enemy force led by the secondary Pallasite Aegir surrounds the Palaestra, Genbu decides to face it head on by himself, while taking the opportunity to share with Koga and the others what he has learned from his teacher, the previous Libra Saint.

Aegir fails to defeat Genbu by himself and the Primary Pallasite Hyperion lends his own sword to assist him. Overwhelmed by the massive Cosmo flowing from the sword, the Gold Saint decides to forfeit his own life in an attempt to destroy it.

As the Saints mourn Genbu's death, Hati appears to resume the assault on the Palaestra until Seiya and Athena appear to drive the enemies away. Having finally decided to confront her sister, Saori takes advantage of the curse placed on her to find out where Pallas is hiding.

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.

Once the saints infiltrate the city, Seiya draws the attention of the enemy allowing Koga and the others to push forward. However, Tarvos appears to challenge Koga to a decisive battle and Ryuhou stays behind to assist him.

As the battle intensifies, Souma and Subaru fall back to assist the other Steel Saints in time to rescue only two of them, Kerry and Emma. Soon after, they are attacked by Loge and forced to retreat once Souma is injured. Surrounded by the enemy forces, Souma and the Steel Saints must work together to break Loge's siege and fight back.

Eden wanders through the city drawn by a strange cosmo when he meets the Secondary Pallasite Europa and is saved by Seiya. Inspired by the Gold Saint to look for a reason to fight, Eden pursues Europa who was sent in a mission to kill Koga, but has a hard time fighting the enemy until Subaru unleashes an impressive power that was dormant within him.

The Bronze Saints rescue civilians who were unaffected by Pallas' curse when Koga has an encounter with a young girl, unaware that she is none other than Pallas herself who has sneaked out of her castle. Meanwhile, Saori's body grows weaker due to her Cosmo being drained as Shiryu, Hyoga, and Shun approach the battlefield.

To increase his power for his rematch against Yuna and Souma, Methone uses a dreadful item given to him by Europa to kill his sister Ymir and drain her Cosmo, and the two Bronze Saints must combine their strengths against the empowered Pallasite, as they reminisce upon the day they first met.

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 ...

On their way to the palace, Koga and his friends meet Celeris, who fights to protect the refugees with the Equuleus Cloth, despite taking heed of the dreaded curse that befalls whoever dons it. They also meet Selene, a young girl who takes care of all the humans who hide underground who has not been frozen in time, and Eden, with something to protect, has to fight Thebe once again, while Subaru and Celeris encounter Hati and have a short battle with him.

Koga's party departs to the palace through the secret passage shown by Celeris. However, worried about him, Subaru returns to assist the Equuleus Saint, and can do little to stop him from sacrificing himself to defeat Hati. Before passing away, Celeris entrusts the damaged Equuleus Clothstone to Subaru, and upon rejoining his fellow Bronze Saints, Subaru unlocks its true power to protect them, becoming a Bronze Saint as well.

Raki arrives at the city surrounding Pallasvelda to assist the others with a delivery of Cloth-restoring Stardust Sand but is attacked by the Pallasite Halimede, armed with a new triple rod. Koga and Subaru appear to protect her, but while Koga's cloth is too damaged, Subaru's suddenly stops moving out of grief for all the Saints who died wearing it. Eventually, he manages to help Equuleus overcome its sorrow and he defeats Halimede with a Pleiades Tempest. Meanwhile, Saori awakens and retrieves the Cloth of Athena to join the battle as well, accompanied by Kiki, Fudo...

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 ...

As Saori and her escorts advance through the city overcoming all opposition, Ryuhou is separated from his fellow Bronze Saints by Paradox, who returns as a Secondary Pallasite for a rematch. Paradox's sister Integra appears to assist him as the new Gemini Gold Saint, while the last of the legendary saints, Phoenix Ikki, prepares himself to join the battle as well.

As Koga and his friends approach Pallas' fortress, Mira appears before them again, but Ikki arrives in the nick of time to protect them. After the Pallasite flees, Ikki reveals to the other Bronze Saints that Pallas is not their greatest enemy, but an even greater foe who is manipulating the whole conflict from the shadows.

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.