De-aged!Merlin, Caring!Arthur, Caring!Knights, Reveal!Fic. If that doesn't say it all, Merlin is turned into a child by ex-druids bent on raising "Emrys" to be their weapon to free magic. Plot is actually just an excuse to write Merlin-as-a-kid fluff. SPOILERS for S4. Set during S4, after episode #whatever, when Elyan is ... you know.