Even more surprising I knew the Fanfic
I'm often "upset" that such great story slipped completely past my radar until some recommends in here or I discover great Fanfics by accident - and there are SO many great ones out there in the Clex Fandom!
OK back to "Earth and Sky collide"... Their whole journey, specially Lexa's, was so deep and paced in like, a healthy acceptance time for grief and such, and the fact that it opened and closed with fire, well...You can see excellent writing in this Fanfic.