It is the secret of the world that all things subsist and do not die,
but only retire a little from sight and afterwards return again.
-All Return Again by Ralph Waldo Emerson
He shouted the words at the top of his lungs, harsh and abrupt. Power flowed through him in waves, more than he had ever felt before. It seemed to come from somewhere inside him, growing with each pulse. His eyes shone golden in the dark, casting a faint light around the abandoned throne room. The gate had yet to appear but he could feel tiny threads of magic weaving together around a small stone table. If he closed his eyes he could almost see them, like a spider's web. Moving closer he picked up a small wooden goblet, pouring in some water from the lake of Avalon that Freya had given him recently, when he was searching for a way to make things better. His words softened to barely a whisper as he picked up a silver dagger. Raising his sleeve, he gently traced the pale skin before cutting into it. As the blood welled from the shallow cut he held it over the cup, catching the drops as they fell. He added a few more ingredients, mixing them together until it created a thick paste. Reaching into the pouch at his side, he retrieved a small, rough crystal. It looked unremarkable and ordinary, but he had retrieved it from the Crystal Cave, and could feel the power inside. As it touched the paste, it slowly dissolved, flashing silver for the quickest moment. Dipping his fingers, he traced runes along the table, speaking them out loud as he completed them. Stepping back he finished the spell, smiling as the runes started to glow.
Come back, Lancelot. It's time to return. As the veil slowly drew open he was vaguely aware of the door bursting open and the knights of Camelot running into the room.
Merlin. No.!" Arthur's voice was faint from behind.
His attention was focused on a faint shadow that was gradually becoming darker. As it got closer he recognized the dark hair and handsome features of his friend. Running forward he caught the knight right as he stumbled.
"Merlin. I knew you would save me"The words were whispered against his neck as Lancelot hugged him. Moisture collected in his eyes as he held tight, glad to have Lancelot back, not caring that his secret was out, and sometime soon Arthur would have him dragged out and burnt at the stake. Right now his focus was the warm body in his arms. His brave and noble Knight.
A/N: I didn't care much for Lancelot until the episode where he sacrificed his life. After that i just couldn't get him out my my head. If you squint real hard you can find some merlin/lancelot.
The water from Freya was just a filler and i assume he could communicate with her like he did with the water the fisher king gave him.