User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-10901795-20130722130637/@comment-5593616-20130723104747

It doesn't really need to have a prophecy, but every book so far had at least part of a prophecy. For SoN, we only got a small excerpt of the true prophecy:

To the north, beyond the gods, lies the legion's crown.

Falling from ice, the son of Neptune shall drown.