She Will Outlive Them (Not)

After the book closes, Twilight's friends remind her of a terrible truth. But she is quick to point out some loopholes and turn things around.

After sending Luster to Ponyville, Twilight's friends remind her of the horrible truth apparent on the surface. That she will outlive them someday because Alicorns live longer or forever. But Twilight points out ways for that not to happen and she takes it rather dark.