Ed and Al become interested in biological transmutation after witnessing a chimera in Lior, so Colonel Mustang introduces them to an expert in the field, Shou Tucker, the Life-binding Alchemist. Meanwhile, a serial killer whose targets are only State Alchemists is on the loose in Central.

After learning about what happened to Shou Tucker and his daughter Nina, the Elric brothers begin to question what alchemy really is. Meanwhile, Colonel Mustang and the other State Alchemists track down the serial killer Scar.

Cooperation between Mustang's cabal and Ling Yao's band leads to the capture of a Homunculus. Unfortunately, their actions also capture the eye of the Homunculus hiding atop the military's ranks.

Truths are exposed when Al finds the one called Father, and Mustang hears the tale of Bradley's creation - but the most amazing revelation is reserved for Ed after he once again breaks alchemy's greatest taboo.