A plot or storyline can be outlined in a more or less random string of images. If you want to, you just have to massage them into shape to make them seem like they were destined to appear together.
Say a french novel was published in 1954. If you are nostalgic, or a scholar, you may want to translate it in a way that expresses the 1950s in France through a kind of amalgamated 1950s english. But, If I want to really relate with the characters, as it were, I have to go all the way, and rather than travelling back in time to put myself in their positions, I bring them forward in time, putting them in our positions, or at least positions more well known to us, living as we do. Kind of like splicing a cultural form onto our culture to see the strange things that happen with its relation to the mores of our place.
If we are going to translate a book, why not really translate it? Change it. We need both kinds of translations, and more and different still, if we are to really translate something. To do otherwise is to fetishize language, do our best to ignore who was speaking it, or at least to try and control them by confining them to the past, or to a kind of nostalgic reverie.
Good lord, listen to me, I’ve only just started translating. And I might be terrible at it. So ignore me, or don’t. It doesn’t matter.