M.L. Martin
Hero
The Abyssal Plague itself, both prelude short stories and full novels, is set within the core setting (PoL for those who love nicknames and acronyms), but the 5-part prelude will be printed in books from a variety of settings.
I looked at the first preview today, and it is set in the core setting, but (SPOILERS)
apparently during the reign of the Empire of Nerath, at least in part. It involves the Elder Elemental Eye, too. This could be a design choice to avoid stepping on gamers' toes by setting the novels in the established past. I actually thought that was the route they were going to go with the Realms' 100-year jump; did that ever turn out to be the case?