Nyx, the changeling, has had enough of Chrysalis and the hive life. The resentment only builds while being starved because of his refusal to let go of a sliver of a memory, that memory is a word, one that brings hope, happiness, and a bit of love. Convinced that this sliver of a memory will be worthwhile, he seeks out the word lingering on his mind. "Fluttershy."
But, his thoughts telegraph more than he wants to as he flees, allowing Chrysalis to track him the whole way. Tormenting him from changeling territory all the way to Ponyville, Chrysalis won't let him go without something in return. To break Nyx's link with the hive, he begs Fluttershy for help who in turn asks the foremost magical pony in Ponyville, Twilight Sparkle to sever the connection.