Sorry about that. RealityCheck's Alicornundrum, Chapter 25. He's been on a huge update binge lately. In fact, just as soon as I left the website, it seems he added Chapter 27! O_o;
http://www.fimfiction.net/story/92069/2 ... chapter-25
http://www.fimfiction.net/story/92069/2 ... chapter-25