This is what should happen.
You are out, on your own at one of those quieter times of day. There’s probably a very good reason for this – please fill in the backstory as you see fit, making sure that you find it plausible and satisfying, because all stories work better when you believe the starting point.
And there you are, ambling down the side of some non-descript bit of water, thinking your own thoughts, or not thinking, or perhaps an odd mix of the two where random things are allowed to float through your mind. But you’re not totally self involved, so you notice when the arm sticks up out of the water. Pale arm. Slender. Not drowning, but not waving either.
Up she comes. An entire, shimmering wet, river weed coated, heart-breakingly beautiful woman. Eyes of sky and water that you know are looking straight into your soul. Eyes that see all that you have been, and all that you could be. There is no judgement in her face, only recognition and you know that she’s been looking for you. She reaches out a hand and offers you…what? A sword that speaks of power and destiny? A pen that is of course mightier than the sword? A paintbrush? This is, after all, your story so it’s yours to know what a watery woman slipping into your time from the place of myth would bring with her.
Of course it is not just an object. It is an act of recognition of who you are. It is not merely permission to go out into the world and do something amazing, it is a demand. Myths do not come round and accost everyone in this way.
Be brave, she says, be bold and be real.
What happens? What really happens, when there are no ladies of lakes bearing Excalibur? What happens when one day is too much like the other and the idiots are many and the wonders few? You do it anyway.
(Now and then I write things for people, because something is wanted. I used to write custom fiction professionally, although usually I have more to go on than I had this time. It would work as a sort of pathworking, I think, adapted to personal circumstance.)