What does a Changeling do when the invasion of Canterlot fails and he gets stranded in enemy territory where everything wants him dead? Well he hides until he can get back to friendly territory of course. That shouldn't be too hard.
Thorax had become the new king of the Changelings and the other Hives are not happy about his alliance with Equestria. Will Equestria survive against the upcoming Changeling invasion? How will they fight against a technologically advanced enemy?