After the reformation of Discord, the Equestrian changeling Midnight Masquerade is given the responsibility of reforming as many of his fellow shapeshifters as possible. His first real rescue in weeks of error finally comes along, only to be followed by a voracious foe bent on their demise. The changelings will need to rally every possible ally they can if they want to survive.
*This story was in the works for almost 4 entire years (99% of this was done before Thorax showed up). See my blog if you're curious as to how in the wide world of Equestria this comes even close to canon.