I agree that Queen Dowager is provoking the king, maybe also threaten him so he finally choose new queen (the one mentioned earlier ?) in exchange of keeping Hee Soo's secret(?). Seems like from the synopsis, QD is asking Lee In to make Hee Soo a concubine instead. From the preview, it looks like Hee Soo will go to Qing,so maybe timeskip too? With Jung Je Pyo in Joseon, Queen dowager knows the secret, The emperor asking Mong Woo to Qing i wonder how they will solve all of it. But please, that scene of Hee Soo and Yi In walking thru grassland..please let it be actual scene and not just dream or something like that... I just hope the last episode can be ultimate episode to finish this series in great note.
Just saw some preview from the final episode, the stone skipping scene gave me anxiety, because it feels like a monologue scene. Hope my prediction is wrong...