Episode 4 of "Twelve" kicks off with a nostalgic flashback, depicting a youthful Haetae trailing behind Tae-san and Mal-rok, bound by an intriguing revelation from Mal-rok: Haetae was conceived with the combined might of all twelve angels. Swiftly, Haetae endeared himself to Tae-san, forging a trio dedicated to safeguarding humanity from demonic threats.
In the present narrative, Bang-wool diligently perfects her archery prowess, while Won-seung conceals his recent activities with deceitful claims. The angelic ensemble later converges for a heartwarming dinner, joyfully reintegrating Mirr into their circle. They receive their monthly stipend, generously donating half to Gan-ji for humanitarian causes, and playfully rib Won-seung about mistaking himself for the dependable Tae-san.
Elsewhere, Mal-rok discovers Tae-san, slumped drunk in his office, haunted once more by nightmares of fallen angels. Awoken abruptly, Tae-san listens intently as Mal-rok unveils the resurgence of Samin, the awakening of Ogwi, and the vanishing soul stone. Mal-rok underscores the urgency of preventing Ogwi from encountering Mirr and mentions Won-seung's fruitless search for Samin. Tae-san concurs, tasking Mal-rok with informing the others about Ogwi and Samin, while keeping the whereabouts of the malevolent spirits confidential.
Meanwhile, Ogwi pays Samin a visit, triumphantly announcing his possession of the first soul stone. The scene transitions to a poignant flashback, revisiting the day of the epic clash where Samin bore witness to Tae-san slaying Haetae, leaving him wounded and fleeing. Just before succumbing to unconsciousness, Samin glimpsed Haetae's cunning concealment of the three soul stones.
Ogwi wields his formidable powers to track down the second stone, dispatching evil spirits to retrieve it. Simultaneously, Won-seung begins to intuit Samin's whereabouts, setting the stage for an impending confrontation.
Back at the Taesan building, Mirr throws herself into an intense workout session with Mal-sook, pushing her limits. Unlike her fellow angels, Mirr retains her abilities, yet she remains puzzled as to why. Following their grueling exercise, they indulge in some snacks, with Mal-sook attempting to delve deeper into Mirr's mysterious visions and her abrupt departure. Mirr firmly denies having any such visions and declines to elaborate on her reasons for leaving, leaving Mal-sook feeling guilt-ridden and forced to drop the subject. Nevertheless, Mirr remains haunted by the specter of her vision, fearing the angels' impending doom. With their powers waned and even their guardian, Mal-rok, struggling under the weight of his residual strength, his frail body constantly tested, the outlook seems grim.
At the clinic, Bang-wool hands Do-ni a precious power supplement, meant to be used during the demon's assault. Mal-rok, chancely passing by, reveals his intentions to resign from the force, promising to share more later that evening. As night falls, Tae-san subtly corners Mirr, inquiring if she has encountered anyone lately, conveniently omitting the fact that Ogwi has returned. He insists that Mirr is the evil spirits' target and urges her to remain inconspicuous within the building's confines. Haunted once more, Mirr experiences another vision of the faceless demon lurking in the cavernous depths.
Returning to the dining table, Mal-rok unburdens his heart to the others about Ogwi and Samin. As the night deepens its shroud, Won-seung tracks the demons' trail but loses them behind an impenetrable dark barrier. In the solace of his home, Tae-san's thoughts drift back to Mirr's pleading not to harm Ogwi, a man he deeply wishes to punish for his role in their family's Tragedy.
Flashing back, Ogwi casts blame upon Tae-san for stripping him of everything. In the present, Tae-san's anxieties revolve around the safety of his cherished family and Geum-soon, their well-being a constant concern amidst the encroaching darkness.
Won-seung and Mal-rok arrive, bringing crucial updates on the demons' whereabouts. Meanwhile, Samin confronts Ogwi with a stark command: to seize the remaining soul stones from Mirr. With confidence, he vows to personally confront Tae-san, well-versed in the tiger's Achilles' heel.
As dawn breaks, the angels awaken to a chilling realization—Mal-rok and Tae-san are missing. Their destination? The very spot where Won-seung last encountered the malevolent creatures. Won-seung feigns ignorance, shrouding his companions in uncertainty. Elsewhere, Tae-san and Mal-rok scout the area, with Tae-san pledging his unwavering protection over Mal-rok.
Samin's devious plan unfolds as he unleashes his demons upon Geum-soon and Man-bok, a strategic maneuver to draw the angels away and isolate Mirr. The angels, their necklaces glowing ominously, fall prey to the trap and hastily converge on Geum-soon's location. Mal-rok and Tae-san arrive first on the scene, finding Man-bok prone on the ground and Geum-soon desperately seeking refuge in a train station restroom.
When Tae-san reaches Geum-soon, she is gravely injured, her arm gushing with blood. With remarkable prowess, Tae-san wards off the demons while Mal-rok strives to rescue Geum-soon. However, more demons encircle them, just as the other angels arrive to reinforce their ranks. Mal-sook and Do-ni bravely volunteer to hold off the demons, allowing the rest to seek an escape route.
Tragically, Mal-sook and Do-ni are brutally overpowered, leaving the remaining angels trapped alongside Geum-soon. Back at the house, Samin marshals another wave of malevolent spirits, their target: Mirr and Bang-wool.
A nostalgic flashback takes us to a day when Tae-san and the angels saved Geum-soon's mother's establishment. They indulged in a feast, with Tae-san feigning indifference but secretly moved by the gratitude shown by Geum-soon's mother. Geum-soon's lavish praise filled Tae-san with renewed vigor. The angels were astounded to witness Tae-san engaging with humans once more, even going beyond the call of duty to assist them. As he departed, Tae-san left more money than was necessary, impressing the young Geum-soon, who saw him as a hero among mere mortals.
