So in episode 18 of Arang and the Magistrate, Arang takes it into her head that the best course of action for her and the Magistrate would be for her to give up her body to the evil Madam so Eun-oh's mommy would be saved. Or at least that's what it looks like. I certainly hope there's more to Arang's half-baked and harebrained plan than that (i.e. Mu-young's involvement, or at the very least a lengthy request list). Otherwise, what?
I get that Arang is panicking because she and Eun-oh might not remember each other once she goes to the afterlife. I get that she wants him to be happy with his mother. But seriously girl, have you forgotten that the spirit you're willing to invite to your body is very evil and creates demons? Have you not considered that Eun-oh might have already committed himself to fighting this thing and you'll only be making things more painful? Have you considered that once said spirit enters your body, she will become nigh invincible and her evil unstoppable?
My mother says it's because love makes you stupid, and because it's more exciting if Arang and Eun-oh will have to face off in the end. I call that bull. It's okay (and exciting) if Arang does have a plan but it goes awry and thus the evil Madam possesses her. Otherwise, meh. Arang was better than this. I know I should believe in the writers, but I've been disappointed before (hello, Bridal Mask). I don't think I trust kdrama writers anymore.