“Finish Line” is episode twenty-three of season three of The Flash and the season finale.
In the previous episode, “Infantino Street”, despite everything, they failed. During his time in the Speed Force, Savitar had worked out how to stop the Speed Force bazooka – using the Philosopher’s Stone, which he called calcified Speed Force, so it didn’t trap him. He had previously duped the others into giving up Iris’ location, something H.R. in particular felt guilty about. Cisco had gone off to confront Killer Frost and she seemed to be winning and Savitar had stabbed Iris, just as he had been originally seen to.
The episode opens with Barry holding Iris’ body. Everyone is shocked. Joe has collapsed. H.R. comes running up, too late, with a gun. The Iris drops one of H.R.’s drumsticks and gasps. And uses H.R.’s transmogrifier device to reveal that Iris is actually H.R. The person who looks like H.R. says ‘Dad’ to Joe, then turns into Iris.
Going back in time, when H.R. said goodbye to Cisco, he then used the bit of Savitar’s suit to track down Savitar and Killer Frost, where he frees Iris. He couldn’t tell Barry or Savitar would know he was coming. They start to leave but the suit piece re-joins the rest of the suit and Savitar sends Killer Frost after them. H.R. disguises them both. Iris isn’t willing to leave, but Killer Frost knocks her down and out, thinking she’s H.TR. and ‘Iris’ asks Killer Frost to spare ‘H.R.’ which works.
Back in the present, Tracy asks H.R. why he is doing it. H.R. did it because he couldn’t be a coward. Because he isn’t a coward. H.R. whispers a message to Barry to tell Cisco and says to go stop Savitar, before he dies. Then Joe tells them that Savitar has taken the Speed Force bazooka. Savitar arrives as Killer Frost is about to finish off Cisco and tells her to keep him alive, as they need him to build something. In the time vault, the by-line of the future headline has returned to being Iris West-Allen.
Savitar is getting new memories and says that something is wrong. Iris isn’t dead. H.R. took her place. Killer Frost starts saying that, if Iris doesn’t die and Cisco finishes, that means the future is changing. Savitar tells Cisco that his is too.
Julian has arrived at S.T.A.R. Labs. He can’t believe H.R. is dead. Joe is confused by time travel, and asks what happens now to Savitar. Because Iris didn’t die, Future Barry will never go down the same path, will not create the time remnants to fight Savitar – and Savitar will never be born. Once the time paradox catches up with Savitar, he will be erased from existence. Joe saw Savitar, though, he didn’t disappear. Not yet, but he will. Perhaps in a few hours. During which he could cause a fair amount of damage.
They could sit around and wait for Savitar to be erased, but that could give Savitar the time needed to pull off whatever he wanted the Speed Force bazooka for. Savitar has been planning this for centuries. He wants to be a god, and needs the bazooka and Caitlin to accomplish this. Joe asks if there’s any good news. Julian says yes. He, and Caitlin’s mother, have devised a cure for Caitlin. Which explains why he was absent during the confrontation. Wally returns at this point; he went to the forest. Cisco, Killer Frost and Savitar are gone.
Cisco is asking Savitar if he has a Plan B. Seeing as Plan A didn’t work. Savitar wants Cisco to fix the bazooka. Cisco states he didn’t make it and doesn’t know how it works. Savitar tells Cisco he knows enough to alter what it does. Savitar wants it turning into an interdimensional quantum splicer. Yes, he does have a Plan B. Savitar will open a time portal, exposing the Speed Force. He will then be shot with the modified bazooka, fragmenting him throughout time, after which the paradox won’t be able to reach him. Savitar will exist everywhere, at every single moment in time. Which does sound kind of like godhood. Savitar wanted the bazooka built, that’s why he let them live. If Cisco doesn’t do it, Savitar will kill Caitlin – and Savitar tells Cisco he now has memories of Julian finding a cure. Caitlin can be Caitlin again, but not if she’s dead.
Barry has been thinking about what Snart told him, about the Flash remaining a hero. So, Barry is going to do the last thing Savitar expects. Which is to meet with Savitar, where Barry tells him that he wants to help. Savitar doesn’t have much time before the paradox hits. If he comes back to S.T.A.R. Labs, they will figure out a way to save him. Savitar asks why would he trust Barry. But Barry points out that Savitar has Barry’s memories. He will remember there is no trick.
Barry is trying to get through to Savitar and it seems to work. He returns with Barry to the lab. The others are not terribly happy to see him. Of them all, Iris handles it the best, and Tracy the worst. However, is Savitar really going to give up his dream of godhood? He already has a plan to stop the paradox, so it isn’t as if he truly needs help. It’s only if he wants to be helped. So it isn’t that easy, and the reason why Savitar needed Killer Frost is finally revealed.
No true cliff-hanger ending to the season, and not really any new story threads leading into season four.