Huge hidden element from Episode 2 Preview you missed...

Look carefully at who is in this room from the preview to episode 2.

We see the usual cast of characters but if you look carefully you will see in the foreground, seated at the chair, is Olenna Tyrell! If you recall she killed Joffrey, but recently Cersei had her son and grandchildren killed by wildfire in the Great Sept. Does this mean that she has fled High Garden? Will she get her revenge against Cersei or will she fail? Jamie talked about taking High Garden, will Olenna Tyrell be there to stop him?