This story is a sequel to The Strangers in Ponyville
Part of the Strangerverse
The changeling known as Driftwood has been a resident of Ponyville for a while now, and Princess Twilight Sparkle does not find his presence as offensive as she once might have. A conversation with Rainbow Dash, however, leads her to the idea that a changeling can be virtuous. A natural scholar, and still seeking a way improve her interactions with changelings, Twiight decides the best way forward is to simply ask Driftwood what, precisely, makes a virtuous changeling.
And perhaps whether that can also make a more virtuous pony.