Hey it's Whiskey with your really belated review :P
I liked the flashback structure. it doesn't always work, but here it does and you were clever to reveal information in both timelines at the right moments :)
I like that you connected the ring-based murder to issues of marriage. It just has this cruel irony to it :D
I must admit, though, that I found the end to be very confusing and had to reread it several times to figure out who was pretending to be who and when...I think what got me tangled up was the sentence with all the boyfriends mashed up into one. Maybe more hardcore fans know the names, but I was swimming in a pool of question marks :P The last sentence did clear up the main point, so if you are afraid others may have a hard time unraveling the twist ending, simplify the last parts and remove any unnecessary names.
In terms of writing style, you had some wonderfully paced and detailed moments when Narcissa wonders about the letter and when she kills the girl. But there were also quite a few ru-on sentences you might want to look over. Some examples: "And yet she does not hear the sound resounding around the empty dining room with an echo that sounds almost ethereal, as if her home knows that it does not house a family any longer – only a family that is now broken." and "The thinness of the material and the imperfections that blemish it suggest the parchment is a low quality version most commonly used by Hogwarts students and impossible to trace due to the vast quantities it is manufactured in." among others.
Also, a few questions:
Why would Poppy/Andromeda resort to sending Narcissa the letter if she could just contact her? Was she trying to break her down through the suspence? What does she get from this? Is she angry that Narcissa wanted to kill her? If so, why doesn't she sound angry when they meet? is she trying to reveal her secret to Narcissa this way? Why, after all these years?
Doesn't a body on Polyjuice Potion turn back to its original form after an hour or so? Did Andromeda get burried within the hour, then? Did Poppy seriously spend her entire life drinking Polyjuice Potion to keep her disguise?
Oh, and, why were Poppy and Andromeda switiching bodies to go and kiss eachother's boyfriends in the first place?
...eh, haha, sorry. I ask a lot of questions :P
Anyways, the story had some uncanny and well palced suspence and was original, to say the least. Just do try to tie up some of the loose ends for dunces like me who don't get the subtleties of the ending.
Author's Response: Hi! I'm so sorry for the delay in responding to this review, real life has been hectic!
Thank you - I was very concerned about the flashbacks, so it's fabulous to hear that you enjoyed it! :) And I'm glad that you liked my choice of murder weapon!
With regard to the ending and the run-on sentences, I decided to send this one-shot off to a beta for improvements, and I've decided that I like the ending as it currently is, as I've received great feedback from it. However, I really appreciate your comments and will keep those in mind for my other/future stories. :)
In response to your questions, it was actually Narcissa who sent Poppy the letter. I've fixed the earlier sections to clear that up, but Narcissa wanted to spook Poppy and make her suffer emotionally, because if Poppy and Andromeda hadn't switched places, Andromeda would still be alive and there for Narcissa to turn to when Lucius and Draco were investigated for being Death Eaters.
Also, in my headcanon, Polyjuice Potion only works on a living body. Once Andromeda was dead, the potion stopped working and therefore never turned Poppy's body back into Andromeda's. And indeed she did - in fact, because she altered her appearance so much during pregnancy, her daughter became a Metamorphagus. ;)
And they switched places in the first place for fun - but Rodney kissed "Poppy" and Andromeda couldn't exactly push him off or she'd attract suspicion (and she couldn't, since taking Polyjuice Potion is illegal).
It's okay, I love questions! XD
Thank you for taking the time to review :)