The seventh episode of Twelve dives right into the secret cave where Ogwi and Mirr have arrived, setting the stage for a poignant flashback. Before Ogwi wielded his powers, he was a mere mortal, entrusted by the enigmatic Light to guard the passageway between the realm of Hell and Earth. Light imbued him with the gift of spotting demons attempting to breach the divide, thus cementing his proximity to the celestial beings and igniting a forbidden flame for Mirr. Yet, angels were strictly prohibited from forging romantic ties with mortals.
Ogwi, yearning for the same divine might as Mal-rok, sought to pray to Light for his powers. However, Mirr was against this dangerous quest, mindful of the sacrifices angels must endure. She sternly forbade Ogwi from embarking on such a perilous journey of prayer, fearing its consequences.
Undeterred, Ogwi persisted in his prayers until exhaustion claimed him, leaving him prone and unconscious. During this time, Darkness, ever-watchful, seized the opportunity to possess Samin's body and make an unexpected offer to the weakened Ogwi. Samin's possessed form promised assistance without giving Ogwi time to reflect on his decision.
Ganji was the first to uncover Ogwi's "betrayal," confronting him with unwavering resolve. Ogwi spared her life out of devotion to Mirr, despite Samin's insistence on ending her existence. He sternly reminded Samin of their respective roles and refused to aid Darkness in his quest for Mirr's soul stone. By the time Mirr learned of the truth, it was already too late, leaving her heart-wrenched with grief and blame upon her beloved Ogwi.
In the present, Ogwi regains consciousness before Mirr, a moment that is both bittersweet and charged with tension. Suddenly, Mirr's soul stone returns to her body, revitalizing her consciousness in a reunion marred by sadness as she accuses Ogwi of betrayal.
On the flip side, Ogwi lays the blame on Light for abandoning him, even as he himself lies injured. Mirr, in a heart-wrenching decision, chooses to leave Ogwi behind and return to Tae-san, convinced that this is the better path. In Seoul, the possessed humans continue their relentless rampage, causing chaos and destruction. The angels, on their journey to rescue Mirr, make a detour to save a few innocent lives. Bang-wool realizes her potential to save humanity and implores her fellow angels to spare these lives.
The ensuing battle is futile, with the possessed humans rising again each time they are defeated. Meanwhile, Geum-soon regains her strength and pities Tae-san for having to fight demons yet again to save ungrateful humans.
As the angels finally get on track with their primary mission, Ganji tries to track Ogwi, but it's too late. Samin arrives at Mirr's location first and overpowers her effortlessly. Ogwi, weakened from his last fight with Samin, is forced to turn to the angels for help to save Mirr. He begs the angels to stall and give him time to heal.
With Mirr in his grasp, Samin returns to the Hellmouth in the Taesan building. He and his minions make their way to the basement, where Samin performs a shocking feat—he revives the four dead angels and possesses them. The other angels are torn when they reach the building and see their siblings turned against them. Tae-san orders them to engage in a fierce battle against the possessed angels while he slowly makes his way down to the basement. Of course, another gruesome fight scene unfolds, with the angels hesitant to harm their resurrected siblings.
In the meantime, Tae-san swiftly retrieves Mirr's soul stone, instantly increasing his power. On the rooftop, Ogwi stands healing and preparing for the impending battle.
Finally, Tae-san reaches the basement and takes out some of Samin's minions. However, Samin keeps sending more reinforcements. He offers Tae-san a chance to switch sides, but Tae-san refuses. The episode ends with more of Samin's minions closing in on Tae-san, the tension palpable in every breath.