Warning: major spoilers ahead for the Season 3 finale of The CW's The Flash, appropriately called "Finish Line."
Season 3 of The Flash spent 22 episodes building up to a final confrontation between Barry Allen and the speedster supervillain Savitar. There has been no shortage of twists and turns between them from the very beginning of the season, which was already plenty twisty due to the Flashpoint timeline. Ever since the midseason finale back in December, we seen Team Flash fighting against time to stop the future in which Savitar kills Iris from coming to pass. In last week's penultimate episode, we saw Savitar actually murder Iris in the present timeline, meaning that he defeated Barry and took the love of his life from him... or so it seemed at the time. In "Finish Line," we discovered that Iris hadn't been murdered by Savitar at all, and it was Savitar's underestimation of Team Flash that would ultimately be his undoing.
Sadly, however, the cost of saving Iris was the life of another member of the team. H.R. used the light refraction device that allowed him to stroll around Central City without being recognized in one final heroic act. With two devices, he switched places with Iris and managed to put himself in her place when Savitar made the final deadly move. Thanks to H.R.'s switcheroo, Savitar failed in his goal to kill Iris, which meant that the chain of events that led to his very existence as a time remnant never happened. H.R. gave his life, and in doing so, enabled Team Flash to take down Savitar.
Of course, H.R. switching himself with Iris wasn't enough to totally take down Savitar. The evil speedster wasn't going to disappear from existence for another few hours, and he proved throughout Season 3 that he was capable of wreaking an awful lot of havoc in not a lot of time. He still had pieces in place that could have turned him into an utterly unbeatable foe for Barry and Co., and it had everything to do with Cisco.
Due to the fact that H.R. temporarily survived his mortal wound, Barry and his pals were crowded around him for a few minutes. This gave Savitar the time to steal the speed force bazooka (and gave me the time to wonder why the Scarlet Speedster wasn't speeding his way to get H.R. to a hospital). He brought the bazooka to Cisco, who was spared in his battle against Killer Frost so that he could do the unthinkable to ensure that Savitar would live on despite the failure of his plan to kill Iris. Savitar demanded that Cisco transform the speed force bazooka into a splicer that would split him into many versions that would be sent throughout the timeline, guaranteeing that he will be present in the past, present, and future.
Cisco, because he's one of the good guys and also not an idiot, refused to help Savitar... until Savitar threatened Caitlin's life if Cisco didn't work his tech magic on the bazooka. Cisco, still convinced that Caitlin wasn't entirely lost to Killer Frost, seemed to acquiesce and got to work on turning the bazooka into a splicer.
Luckily, Cisco is made of tougher stuff than many of us may have thought. After a last-minute rescue from Gypsy, he was reunited with Team Flash, and the reveal ultimately came that he did not transform the bazooka into a splicer. Instead, he reversed the polarity so that when the device was fired, it popped the Speed Force open and freed Jay Garrick, a.k.a. the Flash of Earth-3, who has been stuck in a Speed Force prison for quite some time.
The tides were turning against Savitar in a big way, as Team Flash had a new ally on the scene and his evil plan to send versions of himself throughout history failed. Nevertheless, he wasn't done trying to destroy all that is good and whole on The Flash. In revenge for messing up the splicer, Savitar prepared to murder Cisco, only to be stopped by Killer Frost's crisis of conscience as she stopped him from killing her former friend. By this point, Barry had had enough. Using his speed, he managed to rush at Savitar and force him out of his suit, taking the suit for his own.
Then, we finally got our showdown of Savitar vs. Barry. The Scarlet Speedster seriously considered killing Savitar for all the harm he'd done, but he ultimately refused to sink to Savitar's level and instead settled for socking him in the jaw with a speed punch. Because Barry is a super smart superhero who always takes necessary precautions and learns from his mistakes, he immediately made sure that Savitar was out cold, restrained him, and rushed him to the most secure cell in the pipeline so that he could not hurt anybody ever again.
Just kidding! Because Barry isn't too bright and often fails to learn from his mistakes, he turned his back on Savitar after the speed punch. Savitar wasn't even wholly unconscious from the smack and got up, preparing to go after his nemesis and kill him from behind. Luckily, Iris was there to save Barry's life, shooting Savitar in the back with a handgun and killing him, just before he disappeared into nothingness. Thus was Savitar finally defeated.
And that wasn't even the end of the episode! Although Savitar was defeated, the lengths Team Flash went to in order to put him down had an even greater cost than H.R.'s life. At the very end, we learned that popping the Speed Force open to spring Jay from the Speed Force prison had resulted in a Speed Force assault on Central City as it sought a speedster to take Jay's place. Barry stepped up this time and decided to pay the price for Flashpoint and Savitar himself rather than letting Jay or Wally get themselves trapped. The Scarlet Speedster ended the finale trapped in the Speed Force indefinitely, meaning that in one way, Savitar did win. He may no longer exist and he may have failed to devastate Barry by killing Iris, but he did strike a serious blow that will almost certainly last... until next October, when Season 4 kicks off.
Season 4 is still a ways off, but you can check out what we're hoping happens in our breakdown of big changes we really want from the new season. A big change is happening behind the scenes, so there's no saying what the The Flash will look like when it returns. Stay tuned to CinemaBlend for the latest in TV news, and don't forget to check out our summer TV premiere schedule to discover all your viewing options now and in the coming weeks. Be sure to drop by our rundowns for cable/streaming and broadcast TV renewals and cancellations as well. Our TV season finale schedule can give you all you need to know about your shows ending.