YA/fantasy, a giant claw comes out of a wall and grabs a girl into another world. She has to travel to the four corners of the world, I think her brother follows her

[Louise Joy]

A fairly old book, I read it when I was a teenager so probably 2003 ish, I think I remember the plot being that the sister got dragged into this other world by a claw and had to either hide something or find something at the four corners of this world. I think the brother followed her and at one point the setting was really icy/snowy.

[Ayshe]

The Doomspell maybe?

[Lobstergirl, au gratin]

Louise Joy, are you still looking for this or did you find it?