Führer King Bradley arrives at Lab 3 and informs the guards outside that he will be going in alone to offer assistance to Colonel Roy Mustang. Deep underground, Lust pulls her bladed fingernails from Roy's abdomen and explains again that the Philosopher's Stone is her body's core. Revealing that Homunculi - being closer to the Truth than humans - are the next step in the evolutionary chain, Lust lets Roy fall, shreds his ignition cloth gloves and laments having to let a potential Human Sacrifice candidate die before heading off to deal with the other intruders. Roy lies helpless as Jean Havoc slowly bleeds out on the floor and begs his silent subordinate not to become another one of his comrades to die before him.
Alphonse and Riza Hawkeye follow Barry the Chopper's trail to where the armored soul has finally overtaken and mutilated his human body - a huge, white hall with gigantic stone doors at one end. While commenting on his body's unnatural decomposition, Barry remarks that it must be due to the inherent incompatibility between a soul and a foreign body, causing Al to doubt the integrity and longevity of his own existence and wonder how long it will be before his soul and armor body inevitably reject each other.
Meanwhile, in town, Ling and Lan Fan continue their relatively one-sided battle against Envy and Gluttony, "killing" the two Homunculi numerous times without result. Tired of the endless fighting, Ling asks his opponents to surrender quietly, promising that no harm will come to them if they do. However, noticing that various onlookers have begun watching the spectacle, Envy orders Gluttony to devour both the Xingese warriors and the spectators. But as Envy begins to change form, forming strange scales on his body, a mysterious voice to which Envy refers as "Pride" echoes though the street and scolds Envy's carelessness at allowing Mustang's group to penetrate their headquarters before ordering a retreat. Envy reluctantly obeys and Ling lets them leave without a fight, citing the increased level of danger that they had surely just managed to escape.
At the entrance to the Homunculi's lair, Lust angrily confronts Barry, Riza and Alphonse, lamenting the armor boy's presence as it requires her to kill two Sacrifices in one night. Impatient to sink his blade into Lust's body, Barry charges recklessly forward and is instantly cut to ribbons by her claws and silenced. As she advances on the other two, Lust taunts them, deciding whether to kill Al first or send Riza to join the colonel. Piecing together Lust's cryptic comments, Hawkeye flies into a hysterical rage and empties pistol after pistol into Lust's body, before collapsing in tears when it appears that her shots have had no effect. As Lust moves in for the kill, however, Alphonse blocks the Homunculus' path, shielding Lt. Hawkeye. But when Al displays his new ability to transmute without a circle, Lust further laments the waste of a perfectly good Sacrifice and begins her attack, piercing and carving away at Al's armor as the boy persists in protecting Riza. Hawkeye demands that Alphonse leave her and save himself, but Al adamantly refuses, stating that he will not allow the death of another person close to him when he can help it. Suddenly, Roy appears in the hall and, commending Al's statement, unleashes a torrent of flame upon Lust as Alphonse transmutes an earthen shield to protect Hawkeye and himself from the blast. Lust, knocked to the floor by the blast, regards Mustang in shock and notes that he has cut a Flame Alchemy circle into the skin on the back of his hand and is using the flint of Havoc's damaged cigarette lighter to initiate a spark. But when she asks how the colonel managed to avoid bleeding to death, he reveals that he had used flames to cauterize his wounds shut. Announcing that he will continue killing her until she stays dead, Roy fires off wave after wave of flames at Lust, pushing her Philosopher's Stone to exhaustion. Lust makes a final lunge for the Flame Alchemist as he bathes her in fire, but before she can reach him, her Stone's energy runs out and her body - Stone and all - crumbles to dust. As she dies, Lust commends Roy's resolve, but warns that the day his clear, focused eyes will become clouded by suffering is nigh. His quarry slain, Roy collapses while thanking Alphonse for protecting Hawkeye and asking them to summon an ambulance for Havoc. Just outside the hall, King Bradley eavesdrops on the scene, sheathes his sword and quietly walks away, ordering an ambulance as he reaches the surface.
Unnoticed by anyone, Barry the Chopper's soul remains intact, his blood rune undamaged on an immovable scrap of steel. But his dying body, further drawn to its soul, drags itself over to the wrecked suit and, against Barry's vehement protests, scratches the rune away and ends the transmutation. Both Barrys die simultaneously.
Alphonse returns to his hotel, true to his promise, to find Winry outside waiting for him. Worried over Al's severe damage, but overjoyed at his safe reurn, Winry welcomes him back tearfully. However, as they celebrate together, Al's left arm falls off entirely.
- The symbol engraved on the stone doors is identical to a symbol seen at Laboratory 5 and reads "Pater Abavo Est Creator; Filius Redemptor et Mediator", which translates from Latin into "The Forefather is the Creator; the Son, Redeemer and Mediator", but does not appear to have a real world source. The doors themselves appear to be modeled after the Gate itself.
- In this chapter, Envy nearly transforms to his true form (as revealed in Chapter 51) and alludes to Gluttony's true form (as revealed in Chapter 49).
- This chapter marks the first mention of the Homunculus Pride. Additionally, as it is stated that Pride's "Homunculus aura" dwarfs that of his younger siblings, it is likely that Ling's extreme relief at the Homunculi's departure is due to his having sensed the significant difference between Pride's strength and theirs.
- Lust's final words, commenting on how Roy's eyes will soon be clouded by suffering, is oddly foreboding, considering his future toll for passing through the Gate.
- Whether Barry's human body died as a result of its wounds or because his soul had passed on is unknown, but considering how future talk of souls and bodies always alludes back to Barry, the latter is most likely, establishing that the body and soul simply cannot exist without one another.