Sophie's Surrender is now available on Amazon but there seems to be a slight hiccup with the search function, so here's a direct link.

http://www.amazon.com/Sophies-Surrender-Publishing-Everlasting-ebook/dp/B00E5I9DN8/ref=sr_1_fkmr0_1?ie=UTF8&qid=1374878586&sr=8-1-fkmr0&keywords=sophie%27s+surrender+abby+blake

Or you can search on "Vipers Dungeon by Abby Blake" and all four stories should come up.