Sunset Shimmer is dealing with PTSD, after the events of Anon-a-miss. Rainbow Dash is pregnant with Hoops's baby(she was raped.)
Sunset and Rainbow Dash both decide to get counselling. But bear in mind Rainbow Dash still mistrusts Sunset for her actions at the Fall Formal. When they meet again at the counselling(they have theirs at the same time), Sunset and Rainbow Dash don't know how to react. But as time goes by, Rainbow Dash realises that Sunset isn't who she was before.