I'm looking for a fic I'm pretty sure is on one of the kink memes. It's an old fill but I've gotten a sudden urge to read it again, I think at the time it was a WIP and I hope it's not any more.
anyway, something happens to Arthur and he turns back into a baby, originally I think he was meant to die but Merlin saved him by stopping it before he regressed any further. Because he has to bring back baby Arthur his magic is revealed to Uther who doesn't kill him for some reason I can't remember.
While Uther is upset his son is now a baby, he enjoys raising Arthur once more. As Arthur gets older he falls in love with merlin who is 20 years older than him and merlin is sad because his past lover (who was Arthur) is gone and young Arthur tries to cheer him up and Merlin spends his life teaching Arthur as well as trying to fix the spell on Arthur
does this ring any bells for anyone?