Laziness works to convince Al to go with her, using his mother’s treatment of him. On the street, Wrath tries to recover and remembers his time in the Gate, confusing his memories of Sloth with his childhood memories of Izumi, until he believes that Sloth, not Izumi, is his real mother.
As sloth drives Al away, Tucker begs him to try one more time to bring Nina back. Before leaving, Lenoch knocks Tucker out by creating a ball of water around his head, as Tucker’s role in this is over.
Ed transmutes a nearby metal material into a spare arm for his automail, just as Sloth and Al arrive. Ed tries to convince Al that despite her appearance, Sloth is a copy of their mother, but Al is still taken by Sloth’s performance. When Tucker arrives, Ed sees part of Al’s armor missing and quickly realizes that Tucker has tricked Al. Ed starts the battle by turning his automatic arm into a machine gun, forcing Tucker to retreat and Sloth to turn her body into water, but Al gets in the way. Ed then runs and just as Sloth surrounds him with water, Ed reveals his trap, which is the same type of transmutation ring used against Greed in Dante’s house to seal the homunculus.
Ed then reveals that he has some of his mother’s remains from when he desecrated her grave. This is in a small box, which, to Al’s horror, he seals into Sloth’s body. Lust, who helped Ed create the transmutation ring in the first place, arrives and is thanked by him for her help. He then throws the medallion to her, which she blasts away, saying that she didn’t help him catch it. Sloth wants Lust to state why she betrayed their master, and Lust admits that it was because of her memories, which she believes are created from the strong emotions of whoever did the human transmutation. Al then betrays Ed by grabbing the case and throwing it out the window because he doesn’t want to use their mother’s remains like that. As the recovering Sloth vomits up several red rocks, Al explains that even if they created her, they can’t destroy her. Lust volunteers for their assignment, and when Ed goes after the case, he discovers that Wrath found him first.
Realizing what Ed was up to, Wrath makes it clear that he is determined to protect his “mother”. Ed says Sloth isn’t Wrath’s mother, or his, but she’s an abomination. Wrath seals the pod into his body and knocks Ed back into the building, taking his clue. Once inside, Wrath transmutes numerous weapons onto his left arm and fires them at Lust. Sloth takes this opportunity to turn into water and enter a hole in Al’s armor to take control of him and force Al to go where she previously intended to lead him.
Lust destroys the weapons on Wrath’s arm and Ed has Sloth’s wallet while she deals with Wrath. Lust admits that even though Wrath has no remains that can be used against him, he can still kill him once the red stones in his body are consumed. Wrath can only try to dodge Lust’s attacks, but as he is knocked down, Wrath notices the locket containing Lust’s human remains that she knocked down earlier. Wrath reminds Lust that she can use alchemy and it’s clear she’s in the transmutation ring, and uses the locket to paralyze Lust before she can escape, then activates the ring. Ed catches up to Sloth and can’t fight Al to avoid alchemical reactions as he tries to explain to Al again that the homunculus woman isn’t their mother. Ed starts drawing something on two different identical desks as he dodges Al’s attacks and Sloth thinks he’s trying to use the transmutation circle against his brother instead. However, Ed’s plan is to draw on each half of the circle so that he and Al can connect them and turn both Al’s and Sloth’s bodies into ice, just as she realizes. When Lust begins to vomit her red stones, which seems to be so painful that it makes her cry, Wrath makes her realize that the only reason to become human is to die. Wrath then transforms the weapon on his arm into a sword and kills Lust. He then questions his own desire to become human and when Wrath notices Tucker, he tries to question him in an aggressive tone, only for Tucker to back off in fear.
Ed apologizes to Al for what he did, but Al apologizes for his own stupidity. As Sloth begins to free herself, she admits that she first saw them the night they performed a human transmutation on her mother, who had gone back in time. Dante was in Resembool that night and knew that if the boys were Hohenheim’s sons, this would happen. Dante gave the corpse red stones and carried it to her house. After Sloth eats enough red rocks to achieve her form, Dante convinces Sloth, who was dominated by Trisha’s memories, that he can turn her into a human. Dante put Sloth under Pride’s command to serve in the army under a false name, which Pride had previously used to start the Ishval Civil War to avoid suspicion. Back in the present, Ed realizes that the Sloth is vibrating her cells to generate heat and thaw. After freeing herself and separating herself from Al’s armor, Sloth admits to the Elrics that as Lust said, she has the memories of their mother due to the Elrics’ strong emotions when they created her. Sloth wants to kill them so she can free herself from her memories, believing that no mother can kill her own sons.
As Sloth continues to fight and none of Ed’s attacks work, Wrath appears, taking Sloth away. Ed then stabs her with his automatic sword, which he has converted into sodium so that it can react with Lenh’s watery body and cause it to explode. Sloth is still alive and Wrath, determined to protect her, decides to merge with her. However, this would prove to be his ultimate mistake, as Wrath had absorbed Trisha’s remains into his body earlier. With Sloth no longer able to move, Ed decides to use a similar method when he transmuted Greed’s body earlier. Ed’s transmutation turns Lenh’s body into ethanol and Ed orders Wrath to get away from her as she evaporates. Wrath separates from Sloth and has burns on the parts of his body that were attached to her. The episode ends with Winry watching the battle from the outside, smiling eerily as the Sloth is destroyed.