The protagonist, Celty Loweell, travels to a magical underground kingdom in search for a very important person. down there she finds the clues to finally solve a mystery of her past, but also the knowledge to save her future and her kingdom.

Ruby Heart is being developed, you can see future previews on Steam.

https://store.steampowered.com/app/1460440/Ruby_Heart_Visual_Novel__Otome/