The Flash: Will Nora's Notebook Factor Into "Crisis on Infinite Earths"?

Tonight's Season 5 finale of The Flash was a packed one with not only the resolution of the season's major storylines, but some set up for the upcoming "Crisis on Infinite Earths" event as well. However, those two elements aren't necessarily mutually exclusive. With Nora West-Allen being from the future and part of her entire reason for being in the past being to prevent Barry's disappearance, fans already suspected a major tie to the impending "Crisis" -- and now we may know what that tie is.

Spoilers for tonight's Season 5 finale of The Flash, "Legacy", below.

Let's just rip the bandage off quickly to get the big bit out of the way: Nora "died" in tonight's season finale. Thanks to Ralph Dibny, the team figured out the real reason Eobard Thawne was helping Nora in the future: he needed her to go back in time to help Team Flash defeat Cicada II and destroy the dagger because the dagger was what was dampening his powers in prison in the future. Armed with this realization, the team comes up with a plan to both stop Cicada and also not allow Thawne to win, but it goes awry. They have to destroy the dagger to save Nora from Cicada II, causing Thawne to get free. However, this shift also sets off a new timeline and as it starts to set there's a consequence: Nora is erased from existence, much in the same way Thawne himself was when Eddie Thawne (Rick Cosnett) killed himself during the Season 1 finale to prevent Thawne from existing.

Now, we know that Thawne managed to still exist, and he offers Nora a way to survive as well, but ultimately she elects not to so as not to be corrupted by the Negative Speed Force. She chooses to accept her fate and disappears while in her parents' arms. But while Nora may be gone -- and this new timeline causing "Crisis" to happen five years ahead of schedule -- she did leave behind her notebook and it may have a huge role to play in "Crisis".

You see, Nora's notebook is written entirely in the Time Language she was using to communicate with Thawne in the future. This is significant as the Time Language does not change no matter what happens to the timeline. This means that everything Nora had recorded in the notebook remains, no matter what changes have happened to the timeline. In the episode Iris' discovery of the notebook is a bittersweet one, a way to keep Nora's memory alive with them despite the loss, but more practically that notebook could be very important during "Crisis". As it records the timeline as it was before this latest change, there could be important clues and information within it that will help the heroes when "Crisis" hits -- including, potentially, information that could save Barry from disappearing.

It also could end up being very useful in terms of its record of what may end up lost in "Crisis". As comic book fans know, "Crisis on Infinite Earths" in comics sees the multiverse "corrected" as it were, bringing all of the disparate worlds of the multiverse into one, single, unified universe. If that's what ends up happening with The CW's Crisis, Nora's notebook could serve as a record for what was lost, which could be a whole complicated situation of its own.

Whatever significance Nora's notebook ends up having, fans will have to wait until The Flash returns for its sixth season to find out more.

What did you think of tonight's Season 5 finale of The Flash? Let us know in the comments below.