Now that we know the answer to the big question of the year, aside from who is Prometheus, the remaining question is how is Flash going to stop Savitar? This Tracy girl is working on the trap to imprison Savitar but I think that’s also part of Savitar’s plan. I think Savitar is going to allow Tracy to build the trap so his own younger self can become imprisoned but present day Savitar himself isn’t going to fall for the same trick twice. I still think Savitar is a time remnant of Barry that he has yet to create but I don’t believe he is a time remnant of 2024-Barry from another timeline as I previously suspected. I think 2017-Barry is going to create the time remnant that becomes Savitar only for it to become Savitar. There’s also the issue of how Savitar remembers everything Flash does. While he is future Barry he shouldn’t remember everything down to an absolute fine detail especially if because of his own interventions past Barry is living a slightly different life to him. I think I know why this is.
I think Savitar remembers everything Flash does even despite some of the timeline changes he’s made because he’s remembering every Flash is going to do, so everything Flash is going to to, Savitar remembers doing it himself. Even if Flash makes a different choice than what Savitar himself lived Savitar will remember the difference because he is the future Flash, so basically every choice Flash is going to make Savitar already knows and simply gains these new memories and so he really can’t stop him in a straight up fight. In saying that though if Flash chooses to make a more drastic choice that not even Savitar can stop it might be able to save Iris but it will still cost them dearly.
I think Flash is going to take a page from Eddie’s book and is going to kill himself but to account for Savitar trying to stop him he does something that makes the Speed Force so angry, likely manipulate the timeline again or create a time remnant before he’s actually meant to which Savitar kills so it doesn’t endanger his own existence, and the Speed Force sends the Black Flash after Flash and kills him. Because Flash would have yet to create the time remnant that becomes Savitar then he would cease to exist and Iris lives. While Team Flash will obviously be saddened that Barry is now gone in Iris place they will likely take some comfort in that fact that he won’t become the very monster that they've been trying to stop all year.
I’ve been speculating for some time now that Barry is going to die in Iris’ place and the fact that we’ve been seeing the Black Flash appear throughout Legends of Tomorrow and even Flash is a clear indication of this. Obviously Barry won’t stay dead but I think something should effectively take him off the board until after May when Iris dies and it could provide interesting material for Team Flash next season if Barry is actually gone for a few episodes. Maybe they could do the "Return of Barry Allen" storyline. For those who have read that story you kno That’s just my theory on how they’re going to stop Savitar because I can’t think of any other way.