User blog comment:SayuriDarling/The Sword of Summer Official Discussion/@comment-24055022-20151020030254/@comment-1515612-20151020034938

The book series is a trilogy. It's the third sentence of this post.

Rick said Annabeth will play her role in the series, I believe.

BoO: Continuity error most likely. Rick probably didn't think about it considering Natalie was dead in his mind already so mentioning the two alive people would make sense. She literally only mentions it in like two sentences anyway. I wouldn't think too much into it.