Death, grief, coping.

Twilight isn't particularly knowledgeable about these things, despite the numerous words she's read on the subject. What she lacks is merely experience.

Upon meeting someone who is currently dealing with these things at a far younger age than anyone should have to, she seeks to rid herself of this ignorance.

In her lifelong mission to attain a vast expanse of knowledge, Twilight will begin to realize that sometimes, ponies should cherish the things they don't completely understand.