(Copy of B2MeM comment--I thought you might like to have it here):

You did your resolve to write about the unnamed mothers proud here! Of course they are that, all three, but I think this may be the first time I read a story featuring Gwindor and Gelmir's mother. I like Mirwain a great deal and the way you've depicted her relations with Meril and Alphangil. It seems very realistic, that there is occasionally a bit of tension between them, as well as the support they are giving each other.
And how devastating for Mirwain--not just to lose Gwindor, but Gelmir all over again. And that will only grow worse when she hears more details and they sink in. I suppose she will eventually see Gwindor again (or will she?), but that is going to be a heart-wrenching encounter, too.
I would never have expected a story like this from that prompt, but you have made perfect use of it, at the beginning and in the variation at the end, where they're jumping in the dark.
(I don't know whether it was on purpose that the reveal date was on International Woman's Day, but it does seem a most fitting post!)