Caitlin is a little bit lighter in [Episode 18] because, in this episode, it opens sort of with a direct cut as Team Flash is reeling from learning the news that Nora was working with Eobard Thawne.
And so as they try to unpack and unravel why Nora would have made this decision, they decide to read her journal and that is our portal into going back to the year 2049 — well, flash-forward to the year 2049 — and understanding Nora and how she came to be this way and how she came to be working with Thawne.