- This article is about the manga chapter. For the similarly named 2009 anime series episode, see Episode 4: An Alchemist's Anguish (2009 series).
In return for his assistance in the Bald incident, Edward asks Colonel Roy Mustang to help him learn more about bio-alchemy in case it holds the secret of restoring his body. Mustang refers Ed to Shou Tucker, a State Alchemist specializing in creation of chimeric alchemy who had earned his certification two years prior after producing a chimera capable of human speech. However, Mustang informs Ed that the creature had only said "I want to die" and did not live very long afterward. Introduced to Tucker, Edward explains his intentions and is granted access to the multitude of bio-alchemical texts in the alchemist's private home library. While Edward delves into the books, however, Alphonse becomes acquainted with Tucker's young daughter Nina and their dog Alexander, eventually dragging Ed into their merriment. Unable to find the information they need by sundown, the brothers resolve to return the next day and continue their research, but as they leave, their escort 2nd Lt. Jean Havoc relays a message from the Colonel to Shou Tucker - saying that the "Sewing-Life" Alchemist's yearly assessment is approaching. When young Nina asks her father to explain, he tells her that a State Alchemist must submit the results of his or her research for the year in order to qualify for further grant money. If the result assessment is unsatisfactory, said alchemist risks removal from the State Alchemist program. Nina is confident her father will pass, given how much time he spends studying which comforts him.
The Elric brothers return the next day to continue their studies but decide to spend their time playing with Nina when the little girl reveals how lonely she has been in the past two years since her mother left and her father became engrossed in his research. Meanwhile, Shou struggles desperately to draft a satisfactory assessment report. On the following day, the boys return once again, but are surprised to find the house dark and apparently empty. Searching for the Tuckers, they reach a back room where Shou declares that he has created a second talking chimera. He shows it off to the astonished boys and even teaches it to repeat Edward's name, but when the chimera refers to Ed as "Big Brother" without prompt, Fullmetal realizes the horrible truth - that the creature before him was created by fusing Nina and Alexander together, just as Shou's first talking chimera was forged from his mysteriously absent wife. When Sewing-Life dejectedly confirms as much, Edward furiously condemns Tucker for playing around with people's lives, but Tucker responds by accusing Fullmetal of being the same as him - of playing around with his brother's life and performing Human Transmutation simply to test his own abilities. Hearing this, Edward flies into a rage and begins beating Tucker savagely with his automail fist, causing Alphonse to restrain his brother physically to keep Sewing-Life from being beaten to death. However, Alphonse is also prepared to snap and forces Tucker into silence before he can do so and then apologizes to Nina, saying that neither he nor his brother has the ability to undo the damage her father did to her, and the boys report the situation to East City HQ.
At headquarters, Edward discusses the situation with Colonel Mustang and acknowledges that, even though - as a State Alchemist - he will likely see a great deal more evil and may even be ordered to commit atrocities of his own as a "human weapon" of the military, he will continue to press forward on his path until he has achieved his ultimate goal. But, at the same time, he acknowledges that he is only human despite his abilities or his position and that he was unable to save even one little girl.
At the Tucker estate, a mysterious stranger with an x-shaped scar on his brow murders the guards at the gate and enters the house where a bruised and battered Shou is confiding to Nina that no one understands him. Upon discovering Tucker, the stranger declares to him that, as an alchemist who has strayed from the path of God, he must die. Placing his right hand on Tucker's face, he displays a strange ability and destroys Shou's body from the inside. Noticing Nina who has started to mourn for her deceased father in spite of what he did to her, the stranger apologizes for what has happened to her and repeats the process, asking her to go in peace. As the stranger exits, he asks God to care for the two souls that he has just sent to the afterlife and removes his sunglasses to reveal red eyes.
- In this chapter, it is explained that Roy Mustang's alchemy is made possible by his gloves, which are made of a material called ignition cloth. By rubbing his fingers together, he makes a spark and with the Transmutation Circle on the back, he adjusts the oxygen density around his target.
- In this chapter, it is revealed that Mustang's superiors believe Edward's lost limbs are a result of the Ishval Civil War.