User blog comment:SayuriDarling/The Staff of Serapis Official Discussion/@comment-1515612-20140414043951/@comment-1515612-20140414045551

(Spoilers follow) It has to be way past SoN because Annabeth hadn't met Frank in SoN yet. She only meets him in MoA. Basically this is confirming it's virtually after HoO ends because she has her sketchy relationship with her mom and about how her hat wasn't working. Also, about the fact that she doesn't have her knife on her (aka lost forever in a pit of darkness). And basically RR is setting it up for a complete crossover if he completely runs out of ideas. Seriously.