In Reole, someone appearing to be Father Cornello stirs the townspeople to war, with the Letoist fanatics brutally attacking the skeptics and vice-versa. As the town becomes a war zone, Lust and Gluttony watch from the church belfry, mocking the humans' foolishness and predictability. They are joined by the fake Cornello, who joins in their mockery, and the three remark how the people of Reole have completely fallen prey to their scheme despite Fullmetal's meddling. They remark that humans never learn, blindly resorting to hatred and bloodshed at the slightest provocation, and the person appearing to be Cornello suddenly transforms into a new form at Lust's behest, revealing himself to be Envy, the third among these mysterious operatives. Unfortunately, this transformation is witnessed by Cray, who demands to know where the real Cornello has gone. To silence him, Lust and Envy have Gluttony devour the horrified clergyman alive while they discuss the goings on in East City. While neither of them cares whether Tucker is alive or dead, they ponder the danger of letting this elusive murder roam free around Roy Mustang or Edward Elric; Lust is still incensed that Fullmetal set back their Reole plan, but states that they cannot allow him to die, as he is an important "Human Sacrifice".

Back in East City, Hughes and Armstrong explain to Mustang and Hawkeye that they have designated this serial killer "Scar" because his only identifying feature is the large scar on his forehead. Scar is responsible for five State Alchemist slayings in the capital and ten nationwide and Mustang is shocked to hear that the skilled Brigadier General Grand was done in. Maes suggests that Roy take measures to protect himself since only Flame and Sewing-Life were prominent in East City, but Roy suddenly remembers that Fullmetal is also currently in town. Ed sits in the rain with Al remarking about how their teacher had taught them that even death is part of the alchemical flow and that they should accept that. He wonders how he can be so stupid as to hope to overturn such a basic natural law, even now after having suffered so much for it. However, just then, the boys are attacked by Scar, who proves himself capable of destroying anything his right hand touches, the boys flee through the city with the killer hot on their heels and are stopped when the scarred man traps them in an alley. Forced to fight, the boys charge, but find themselves outmatched as Scar tears a gaping hole in Alphonse's side, immobilizing him, and obliterates Ed's automail arm in a flash. Ed collapses to the ground as the immobilized Alphonse, terrified for his brother's safety, cries out desperately from his place on the pavement. Frozen in shock and despair, Edward asks Scar if Alphonse is one of his assassination targets as well. Scar explains that, while he will kill anyone who gets between him and his objectives, Alphonse is not one of his priorities and so Edward offers his own life up in exchange for Scar's word that Al will escape unharmed. Scar agrees to Fullmetal's conditions and moves in for the kill, but Alphonse - vehemently opposed to his brother's resignation - begs Ed to flee.

Fortunately, Scar is stopped by the timely intervention of Colonel Mustang and his forces. Roy declares Scar under arrest for his crimes, but Scar responds that alchemists - who profane God's design by altering the shape of natural things - are the criminals who deserve punishment. Goaded by Scar's words, Roy attempts to take on the murderer with his powers, but is rescued and reminded by Lt. Hawkeye that his Flame Alchemy does not work properly in the rain. While Scar is distracted by Roy's actions and his own threats, Major Armstrong delivers an attack from behind and formally introduces himself as the "Strong Arm Alchemist". Armstrong and Scar engage each other in battle and, observing and analyzing the alchemist killer's counterattacks, the Major deduces that the mysterious assassin's "power" is, in fact, alchemy with the "reconstruction stage" omitted, leaving all matter transmuted by him in the second stage - the "deconstruction stage". As Roy wonders how an alchemist can put himself against other alchemists on principle and 2nd Lt. Havoc explains to Edward that Scar is the one who killed the Tuckers, Scar realizes that Strong Arm is a far more dangerous opponent than originally thought and changes his attack pattern to exploit the Major's wide swings. But when Armstrong suddenly pulls back from combat, Scar realizes that the frequent openings were intentional - bait to distract him while Lt. Hawkeye prepared to open fire with her rifle. Scar manages to evade her shots but a bullet grazes his face and knocks off his sunglasses, revealing the irises of his eyes to be red. Seeing this, Armstrong and Mustang recognize Scar as an Ishvalan. Not having anticipated so many foes and unexpected turns, Scar cuts his losses and deconstructs the street beneath him, escaping into the sewer system. Ed scrambles to Al's side to check on him as the others marvel at the younger Elric's hollow constitution, but Alphonse angrily and violently berates his brother for giving up to death when he still had a chance to survive, commanding him never to do so again.

Back at headquarters, Mustang explains to the Elric brothers that the region of Ishval in the east had been the center of a civil war that had begun thirteen years ago when an Amestrian soldier accidentally shot and killed an Ishvalan child. After seven years of fighting, the State Alchemists had been sent into Ishval to end the war by eradicating all of the Ishvalans in the region. As one of the State Alchemists involved in the extermination, Col. Mustang asserts that there may be some justice in Scar's killing spree, but Edward rebuts, saying that Scar is merely disguising his own revenge as righteousness. As Roy vows to hunt Scar down and eliminate him, Edward asserts that his lost arm makes it impossible to repair Al's armor while guaranteeing the integrity of his bound soul. Therefore, he declares that his next move is to visit his automail mechanic.