Now an official state alchemist, Ed takes a closer look at Tucker's chimera experiments and begins to realize that something wrong has been going on.
Full Synopsis: Plot Details Follow
As Lt. Colonel Mustang gives Ed his State Alchemist's silver pocketwatch, and Tucker is up for his annual re-certification as a State Alchemist. Ed becomes a little suspicious of Tucker's wife's leaving, and Tucker's chimera studies, after he finds a burnt-up letter written by Nina to her mother in the trash. Ed goes to the National Central Library to research Tucker's chimera research, but an archivist says that Tucker's research cannot be accessed without Brigadier General Basque Grand's clearance. On his way out, Ed rips the sleeve of a strange man, revealing an arm covered in odd tattoos. The man runs away, asking his unseen "brother" about a curse. Ed goes to Maes Hughes who informs him that Tucker's wife died before Tucker arrived in Central two years ago and the only thing that the Chimera he created back then said that it wanted to die. Before Hughes can say anything further, he is called away to investigate the workings of a recent serial killer and Ed frighteningly remembers his mother when he sees the reaction from the child of a recent female murder victim when he accompanies Hughes to the murder site.
That night, Ed wakes up and Tucker correctly assumes the situation with their bodies for having committed the taboo after hearing Ed talk about his mother while he was asleep. Ed and Al are then forced to go away from the Tucker house after Grand worries that Ed is getting into this chimera thing too deep. Ed and Al sneak back into the Tucker house the following night, and find a basement full of strange caged animals. Tucker calls them into the back room, where a dog-goat-like creature with brown hair lies next to him. He introduces it as a chimera capable of human speech, but it's mannerisms and what it says reveal the truth: Tucker transmuted his own daughter Nina with his dog, Alexander, to create this monster just like he did with his own wife two years ago. Tucker and Nina/Alexander are taken by the government, where Grand wants to cover it up. Ed overturns the police truck, intent on rescuing Nina and de-transmuting her, but she runs away. She is found by the strange tattooed man, whose tattoos glow red when he touches her. Lamenting over Nina being a sin against nature and in such pain, he prays to God that she be re-accepted into his light before deconstructing the transmuted girl, thereby putting her out of their pain.
The way Grand had the Elrics removed from Shou's home at gunpoint confirms he knew the secret behind Shou's first chimera and didn't care. It could also mean that he was going to be complicit with what Tucker was going to do to his daughter.
The ending credits of this episode is changed to a montage of the good times Nina and Alexander had with the Elrics, and a picture of Nina and Alexander sleeping side by side.