Well it had to happen, every manga comicbook needs a beach episode, so here it is XD each girl of each of my comicbooks on a vacation :D
Why is Mimi broiling alive in that outfit? Well Mimi is from the Victorian age, back then this was how women HAD to dress, litreally if the skirt was shorter or you worn no pants you could get arrested for "immoral dressing". And that wasn't a windy and light nylon like today, that was 100% wool.
If Mimi is wearing her contemporary outfit than why is Radoslava wearing a modern Japanese swimsuit? Weeeeell back in 17th century there was no concept of "recreational" bathing in the sea so she shouldn't even be on this picture, but being a Rusalka monster she will *spoiler alert* survive till the modern age.