Warning: This article contains spoilers for The Flash season 5, episode 8!

This week, The Flash celebrated its 100th episode with a trip back to the past.  In "What's Past is Prologue", Team Flash decides that the only way to stop Cicada in the present is to create a dampener for his power-dampening dagger. To do so, they needed to collect items from the past: a piece of Savitar's suit, the tool Zoom used to steal Barry's speed, and dark matter from the fateful particle accelerator.

The time travel aspect allowed the show to revisit some of the previous big bads as well as some the moments that turned Barry into the hero he is today. It was touching to see Barry share with Nora some of the experiences in his life that weren't in the Flash Museum - including the truth about his relationship with Eobard Thawne aka the Reverse-Flash. That piece turned out to be key because as the end of the episode revealed, Nora is really working for Thawne in the future.

Read More: The Flash Midseason Ending: Nora Works For Future Reverse-Flash

The reveal about Nora definitely left us with some major questions about where Team Flash goes from here. Here are our biggest questions from The Flash's 100th episode.

8. Why Didn't Barry Ask Harry For Help in a Time Before His Mind Was Weakened?

The Flash Season 4 Harry Thinking Cap Bus Metas Janet Petty Edwin Gauss

While escaping from Zoom (and a time wraith), Barry and Nora damage Zoom's speed stealing device. The only person smart enough to fix said device is Earth 2's Harry Wells. However, Barry says he is not an option due to the state of his mind. Harry lost his intelligence due to the thinking cap he invented in season 4 to help him outthink Devoe. But this whole episode was about time travel. Couldn't Barry and Nora have traveled back to a time before he invented the cap (say season 3) and asked him for help then? This would have prevented them from having to seek out the help of Thawne and therefore prevented Thawne from meeting Nora. Wouldn't asking a trusted friend for advice have made more sense than asking Barry's arch enemy?

Of course, The Flash wanted to bring back Barry's biggest rival for the 100th episode so it makes sense they found some way to handwave away the reason Harry couldn't be asked for help. Thawne's presence raises the stakes in the episode and complicates things once his involvement with Nora is known. So we can allow it even if it doesn't make total sense.

7. Does Dr. Ambres Have A Larger Role To Play In The Flash Season 5?

Dr. Ambres seems to be everywhere. Not only is she the doctor for Cicada's niece, but this episode revealed that she was also on call the night of the particle accelerator explosion, specifically when Thawne-as-Wells and the lightning struck Barry Allen were brought in. All of these things cannot be a coincidence. Dr. Ambres must have a more important role this season than how she initially appears.

Throughout The Flash season 5, Dr. Ambres has been helping Cicada. In the flashback episode, "O Come, All Ye Faithful", she was the one who placed the blame for Grace's injuries on metahumans. If she isn't the real big bad of the season herself, maybe she is working with Thawne. She could have discovered the truth the night of the explosion and continued to work with him recruiting Cicada to his cause.

Read More: Theory: Flash's Season 5 Villain Isn't Cicada, It's Dr. Ambres

6. How Did Barry Learn Nora's Time Language?

When Sherloque finds Nora's journal with indecipherable scribbles, he has questions. Nora claims she made up a "time language" as a way to record her time with her father even if the timeline changes. However, this is also the same language Barry was writing in when he emerged from the speed force in The Flash season 4 premiere. And apparently Thawne can read it too since all of Nora's messages to him are sent in this code. Can all three read the language because of their connection to the speed force as speedsters?

When Barry came out of the speed force there were a whole bunch of clues hidden in his mad ramblings. Could this time language hold even more about the future? Whatever it is, Nora seemed pretty uncomfortable with Sherloque's questioning. Is she just because she is unwilling to admit Thawne is the one who really created the the language or is there something more?

5. What Does "The Timeline is Malleable" Mean?

When Cisco decoded Barry's writing from his time inside the speed force he could only translate one line: This house is bitchin. Similarly, Sherloque is only able to read one line of Nora's journal which states, "The timeline is malleable". Nora has been compiling these notes for Thawne. Has she been sent to the past as a guinea pig of sorts to test this very theory? Is she there to see if the timeline can indeed be changed in ways without breaking completely? And if so what does this mean for the future?

If the timeline is malleable that means events can change. This is dangerous knowledge for anyone to have, but especially Thawne. It will be interesting to learn how Nora came to this conclusion and what it means for the future. The Flash already plays pretty fast and lose when it comes to the timeline, but this could change everything we thought we knew about how time travel on the show works.

Page 2: The Flash Questions About Nora & Reverse-Flash

Nora West-Allen The Flash 100th episode

4. Why is Nora Working for Eobard Thawne?

One of the biggest questions to come out of this episode is just why Nora might be working for Thawne. Sure she didn't know that he killed her grandmother, but she did know that he was one of her father's greatest foes. What could possibly be her reasoning? No matter what the answer is, one thing is for certain: Barry is going to be crushed when he learns the truth. Even if Nora's intentions for traveling back in time remain the same, she has done it under false pretenses. Adding on top of all of that the fact that she has been sending Thawne intel about the past and she can say goodbye to any relationship she has built with Barry. It's going to have to be a pretty good reason to make him understand her actions.

But what if Nora is doing all of this to save her father? Nora told Barry the reason she wanted to meet him is because he goes missing in the future. In the article written by Iris in the time vault the reason for this disappearance is connected to Barry's fight with the Reverse-Flash. As a Flash superfan, wouldn't Nora know all this? Perhaps she is working for Thawne in order to find a way to change the timeline and prevent their fight.

3. Did Reverse-Flash Help Nora Come Up With Her Plan?

Now that it's been revealed that Nora is working for Thawne, it calls a lot of her actions into question, especially in The Flash's 100th episode. Nora had a pretty quick answer on how the team could find everything they needed to create a weapon to fight Cicada and, while her plan didn't exactly work, it came pretty close. Did she come up with it on her own because of her encyclopedic study of Flash history? Or did Thawne give her the idea? And if he did, what would be his motivation in helping to defeat Cicada? Thawne is calculating, if he wants to save Barry, it's for a reason. And now because of Nora's connection to him, her actions and motivations must be called into question.

2. Is This the Real Nora West-Allen?

Nora introduces herself to her family

When Thawne first meets Nora in the past he calls her Dawn. What at first seemed like a fun Easter Egg for comic book fans might actually mean something more. Now that we know Thawne and Nora are working together in the future is it possible that there really is a Dawn Allen? Could Nora be a twin, taking Don's place? Or is the Nora we know an imposter sent by Thawne? Is there even a Nora at all? Because she's from the future there is no way of knowing if anything she says is true.

While Nora has seemed genuine in her love of her parents and excitement to meet them, some of her actions have also been suspicious. She spied on Team Flash for awhile before introducing herself, she hasn't told anyone the truth behind who sent her, and she's constantly taking notes which we now know she uses to update Thawne. This doesn't seem like someone who just wants to spend some time with her missing dad.

Read More: FLASH: How A Batman Beyond Easter Egg Reveals Nora Secret

1. What Is Reverse-Flash's Plan?

Eobard Thawne Reverse Flash in 2049 on The Flash

Whether he knows it or not Reverse-Flash is once again back in Barry's life and pulling the strings. But what is his plan in The Flash season 5? Right now it seems to be relegated to reconnaissance; he has Nora collecting information in the past and sending it to him in 2049. Did he choose Nora for this mission to cause Barry the most pain when the truth is revealed or does she have a specific role in his plan? Why does he need information about the past anyway? And what does this all have to do with Cicada?

Thawne doesn't look so hot either. Traveling through time seems to have taken its toll. The figure we see at the end of the episode looks like a mixture between his stolen Harrison Wells face and his own as Eobard. Could his depleting form have something to do with why he is after Barry once more?

Since this episode is The Flash's mid-season finale, we'll have a bit of a wait before any questions are answered. Next up for Team Flash is the Arrowverse crossover, but those episodes usually don't deal to much with solving the individual shows' mysteries as much as they do spinning off new shows and creating fun hijinx.

Next: Arrowverse Elseworlds Tease Explained: 1990s Flash vs The Monitor

The Flash season 5 continues with episode 9, "Elseworlds, Part 1", at a special time on Sunday, December 9th at 8 PM on the CW.