River boy

Knowing that he is dying, Jess's grandfather insists on returning to the river he had known as a boy to finish a special painting and fulfill a life-long dream. At first, Jess cannot understand why this painting is so important to her grandfather, especially since there doesn't seem to be any boy in it at all. But while swimming in the river herself, Jess begins to feel the presence of a strange boy. Could this be the same one her ailing grandfather struggles to paint? And if so, why has he returned?