Avengers & Alchemists, Assemble!

Six years after Promised Day, Ed, Al, Ayala, & Chester are on their way to Central Command when an unknown person with powers they've never seen attack them. Despite Mustang's & Nala's help, their attacker is successful & now Ed, Ayala, Mustang, & Nala are in a whole new world that needs their help against a tyrant. How will they survive this new world & the tasks asked of them?