Nothing happens.
The river flows. Leaves fall. They spin and drift. Rot.
A little thing flicks from the open ocean into the estuary, borne by dark currents from its birthplace thousands of miles to the north. It has burst from the egg, a minute glassy leaf, gut and nervous system visible as fine wiring beneath the skin. And, in the genetic either/or, female.
She has been swept up. She has been carried south until she came to this estuary where she has swum upriver. Just one tiny sentient creature among thousands.
She has made her way against the current to a safe place, beneath a muddy bank.
She settles into her life.