When my darling and I were reading a lot of fairy-tales at bedtime, we read one which we've not been able to find again since in the works of Andersen or the Brothers Grimm.
A young man is out in a boat on the river, and overturns. Drowning in the weeds at the bottom of the river, he's saved by the river fairy/sprite, they fall in love and he can now live underwater.
But he hankers after his old friends and acquaintances 'up above'. Oh, to see them again and to find out what's happening in the wide world!
So she lets him go, as the Hebridean witch-queen Thorgunna released Lief Ericsson, on condition of his return.
And like Lief, our young man forgets his betrothed and his promise - and eventually is due to marry someone else.
Come the wedding day, and it's starting to rain. By the time bride, groom and guests are in the church, it's raining stair-rods (I paraphrase) and the river is rising fast. Before they get to 'I do', the river is sweeping all before it - church, bride, groom, guests and all. That's what comes of slighting the river-fairy.
I told you my daughter liked the doomy, gloomy stuff.
Anyone know what the story's called ?