(Magic, elves, another world, dolls, not sure if there'll be a couple, we'll see how it goes.)
This is a world filled with magic. As part of the trial required of an heir, Yeta must enter the otherworld connected to her family when the magic grimoire opens, find a fragment of space-time, then locate that world's magic grimoire and return to her family.
So this is the world inside the magic grimoire?
Wait, why can't I move?!
A doll? I, the young lady of the house, have become a doll!
Oh, those two young ladies are arguing. This is entertaining.
As a doll, Yeta's movements are limited. Maybe the first thing she needs to do is find out where her body is.
Yeta is about to travel far away with Bella when she receives a mysterious invitation. Who sent it?
Yeta decides to go see for herself.
A remote, mysterious old castle, a curse and a blessing, and dolls that can have hearts?
What nonsense is this person talking about?
Yeta thinks it over and decides to believe him anyway.
If it's true, she can get her flesh-and-blood body back even if she can't find it for now. Not a bad deal.