This takes place after the battle against Morgana all the way up to when Merlin calls Kilgharrah for his aid. Of course I own nothing.
Merlin struggles with the weight of an almost unconscious Arthur. Frustrated, exhausted, and despairing, Merlin yells out to Kilgharrah. "O Drakon, e male so ftengometta tesd'hup'anankes!"Collapsing Merlin struggles to catch his breath. He rolls to his side and gets up. He grabs Arthurs arms and hauls him up. "Just a little longer, Arthur." Merlin manages to wheeze out. He hobbles further with Arthur on his back. Wing beats can be heard. Kilgharrah flies down to them. "I would not have summoned you, if there was any other choice. I have one last favor to ask." Merlin drags Arthur onto Kilgharrah and they fly to the lake.
Merlin pulls Arthur from the dragon and drags him over to a small boat.
"Merlin, there is nothing you can do." Kilgharrah says in a comforting voice.
Merlin whips around to face Kilgharrah. "I've failed?"
"No, young warlock, for all that you have dreamt of building has come to pass."
"I can't lose him! He is my friend!"
Kilgharrah looks out onto the lake of Avalon and ponders what the course of life has brought for this young warlock. He has grown rather fond of this Dragon Lord and although the path before them is laid out, it is not set in stone. "What consequences are you prepared to deal with, if you were able to save Arthur Penndragon's life?"
"Anything, everything. Is there a way?" Merlin's eyes pleading.
"I have lived a long life. My time is almost upon me. I told you once that I would aid you as long as I had strength in my body. I will keep my word." Kilgharrah lowers his head to the unconscious Arthur. He takes a deep breath and releases his breath upon Arthur. Gold whisps of air surround Arthur. The blade piece lodged in Arthur's heart came out and went into the dragon. In a brief moment, the world stood still. An orb of bright orange and red came from Kilgharrahs large throat and floated down into the wound Arthur was inflicted with. A giant burst of energy knocked Merlin to the ground and he became unconscious.