Threat of the.... It

OK, I found a story I started, and I think I'll continue it.

Eva is a super poor orphan.  She makes her clothes out of her own hair, therefore on Orphan Day, she never gets taken home.  She always just lives out in the trees with the other orphans.
Jenna is an orphan.  She's not too poor, but she is an orphan, so she still lives in the trees and bushes.  She is very shy.  She looks up to Eva, who is very nice and caring.
But when Jenna is too scared to speak to a bold orphan named Kim, things get scary.  A strange thing that looks like a girl is flying in the air, chanting something that is putting all the orphans into a frozen state.  And every time one of the orphans falls to the ground, the thing gets more pretty.  What she chants points to the fact that Eva is the only one who can save the orphans.  What is this thing doing, and why is she getting prettier?  Will Eva go to save the orphans?  Can she?