I'm catching up on Arrow, and I'm currently in season 5. I think I missed something between episodes 15 and 16.
Episode 16 starts out with Oliver in the mountains at some place assuming that Prometheus is a student of Talia. I don't recall seeing that covered in episode 15, and I checked the order to watch to make sure it wasn't revealed in another shows' episode. I didn't see a flashback explaining this either.
Is this a plot hole, or did I miss something somewhere?