Here I share with you my idea for the first arc in Season 4 of The Flash TV show:
Daniel West and the return of Barry Allen!
What if we started the season with Daniel West? In comics, he is Wally´s father and also a Reverse Flash and this seems like a good opportunity to bring him into the show.
Have a 3-4 episodes long arc (I´m writing the longer variant) as Wally is currently „The Flash“, the only speedster in Central City. He is loving the fact that he can be there for people, but working alone has its downsides – there´s much more responsibility and work. He is bearing the safety of the whole city on his shoulders and we see him struggle with that a bit.
Then, to top it all off, a new speedster appears. He has black, dark red and golden color scheme, his suit looks a lot „armor-y“ and his face seems to be damaged, scared, burnt even.
He starts by breaking into Mercury Labs (as everyone evil speedster does) and there he is confonted by Wally. He hesitates and then runs away after a brief battle, which Wally would describe as „The speedster was holding back“.
They would try to find him and figure out how to stop him and the episode would end with this speester coming to the West house and telling Wally that he is his father, Daniel (obviously, his last name is not West).
The second episode (titled You are my father) would be your classic and favorite CW drama, where Wally would be „sure“ that Joe is his father, Joe struggling with the fact that it may not be true and the whole West family and team Flash trying to deal with Daniel and all of this.
We would also get Daniel´s backstory. He and Francine (Joe´s wife, Wally´s mom) were „drug buddies“ as they were using together back when Francine was still living with Joe. And as it happens, they had a thing and Francine was occasionally cheating on Joe with him.
When Francine left, Daniel helped her get a new life in Keystone, but soon after that he was arrested. he spent years in and out of prison until finally deciding to find Francine and get together with her. But he finds out that she died and that her son lives in Central city now. He is shocked, as he did not know she was pregnant and he also starts believing that the son was his. His age adds up to their affair.
This leads him to Central city, where he is hit by the speedforce storm while driving and so his car´s metal plates merge with his body, creating this suit and making him look like a monster. This is no condition to meet his son and so he just watches him. He watches him live with Joe, being happy and all that and he becomes incredibly jeleaus. And angry. Joe is once more in his way, as he remembers how Francine was putting Joe and Iris first back in the day.
But while watching them, he discovers his powers and tries to get control of them. He also figures out that Wally is the Flash/Kid Flash (because he is watching him) and one time, when he gets the courage, he tries to introduce himself, but as he runs behind Wally, he siphon´s (gets charged) by his energy and time jumps to few days ago.
Before realizing what just happened, he is pulled back to the present and then he gets it – he can travel back in time to make sure he is there for Wally during his childhood, but he needs insane amount of „speedster energy“ to pull it off and to not get pulled back to the present again.
That´s why he breaks into Mercury Labs, to steal their new prototype, a device that can theoretically control the speedforce storm if it ever happened again. The ultimate way for Daniel to get enough energy to pull this off.
That´s his story and even it leads to Wally and the team to trying to tell him how bad of an idea it is – time travel and changing past have terrible consequences, just look at what happened to Barry. Plus, Wally does not believe that Daniel is his father. Joe wants to be as sure as Wally is, but he can not be. It is only after Wally tells him how Francine talked about him and how she never mentioned Daniel, Joe calms down and get a piece of that certainty from Wally. And Wally is right (* I´ll get back to this).
The second episode would end with enraged Daniel, who does not want this to be true, as he is persuaded that Wally is his son and to make sure of it, he decides to move forward with his plan and go back in time. He will raise him and Wally will be his. No matter what.
He gets to that device in Mercury Labs and steals it. That´s how the episode ends. In the „post-title“ scene we will see Barry emerging from a time breach.
Third episode would be titled Return of Barry Allen and would start with the team hunting down Daniel and Barry joining them. They are filled with joy that he is back, but Jay (who they called to help them with Daniel) feels that there is something frong with this Barry.
As the episode goes, everyone starts feeling that and even Barry´s lightning color is making them uncomfortable – it goes from golden to orange to almost red and in a final battle he will beat Daniel senselessly, while grunting that he is the real hero. These lines (and the fact that his eyes start to glow red-ish a bit and he starts vibrating from all those emotions) lead to Cisco realizing that it is not Barry at all, but it is the reverse – Eobard Thawne, who is just disguised as Barry (* check Notes).
Wally and Jay would then go after im and Daniel would slip away. After battle with Thawne (who seems to strongly believe that he is the real Barry Allen) they defeat him and he comes to his senses and is devastated by the truth about himself. Then he is thrown into his time by Wally and Jay.
The episode ends with Jay telling the team that after what they have told him about Thawne, he believes that this is how he became truly the reverse of what Flash stands for. That this started it all. In the „post-title“ scene Daniel turns on the device, finally being able to acomplish his goals.
Episode four would be all about stopping Daniel. But now he is charged with the speedforce and so he is way faster and stronger that them. Now he can achieve his goal. To prevent him from doing that and after he beats both Wally and Jay (maybe even Jesse), the team would go for a „secure choice“ and that is trapping Daniel in the speedforce and releasing Barry. An exchange, that helps them in two ways – they get Barry back and they get rid of Daniel. This would also be continuing the fact that the speedforce prison needs an occupant.
This would be an interesting way to start a season, giving development to Wally and Joe, using the fact that Wally is „The Flash“ as an opportunity to give him an interesting villain and to show this side of Thawne´s origin. It would also give them a reason to not have two (or more) speedsters all the time, as Wally would like to take a break after all of this. Then he could return to Keystone or go with Legends etc. so he would not be present all the time, just when he is needed.
If Daniel is Wally´s father (not sure if I want that to be a thing) and Wally finds out, he would not tell Joe, but he could have Cisco vibe him in the speedforce prison every once in a while to talk to Daniel. He would still consider Joe as his father though.
When Thawne is beating up Daniel, the technology that makes him look like Barry could break and so we would have Eobard in a Flash suit during the battle with Jay and Wally. But it would mean having to make Matt Letscher a costume just for one episode/scene and I´m not sure if CW would do that, even though it would be awesome.
Theoretically, Thawne could just be Thawne but in a Flash suit, coming to help Wally with Daniel. But the team would reject him because they know who he becomes, which drives him crazy. He would tell Wally that he is not „THE Flash“ on which Wally would say „Neither are you!“ But the battles with Daniel and Team Flash would still happen.