Fourthed by Marlee Cross. Talis is an amazing writer and this is probably her best work. All the character's emotions feel geniuine and even though the way everyone (especially Usagi) acts around Chibi-Naru isn't right, you can understand why they feel the way they do. I cannot recommend this fic highly enough.
An AU where Usagi and Mamoru had a daughter who wasn't Chibi-Usa, this fic shows just how much a single person can touch others... and how hard it is to let go. Truly heartbreaking in some aspects, it's a well written fic that I highly recommend,