The third season of The Flash (The Flash), an American television series, consists of twenty-three episodes1 and aired from October 4, 2016 to May 23, 2017 on The CW, in the United States. The plot follows Barry Allen / The Flash with his team and the time changes related to time travel and the aftermath of The Flashpoint.
After his father died at the hands of Zoom and the latter was defeated, Barry finally traveled back in time to save his mother, which totally changed the present. This alternate universe is called the Flashpoint. Barry quickly notices the changes: Joe and Iris no longer speak to each other, Caitlin possesses the Killer Frost powers that she did not have before, Cisco's brother is dead and as for him, he discovers that he has a new co-worker. Barry is quickly confronted by Dr. Alchemy, a strange masked man capable of empowering anyone, and then the frightening Savitar, self-proclaimed the God of Speed.
Barry is living the life he has dreamed of for three months in the alternate reality he created by saving his mother from the Flash Negative. Both parents are alive and another Flash, who is none other than Wally West, called "Kid Flash", protects Central City. As he begins to reuse his powers, Barry slowly loses the memories of his past life before he rewrites history. It was then that Eobard Thawne warned him: time was going to make him pay for his gesture. During the confrontation between another supersonic called Rival and Kid Flash, Barry's ally, Wally is injured.
Barry finds out that Clariss obtained her powers thanks to Dr. Alchemy, a strange masked man who lived through Flashpoint and plans to have everyone who obtained powers in the alternate reality get them back. Overwhelmed, Barry manages to stop Rival with the help of Cisco, who has better mastered his Vibe powers since Barry's time travel. Everyone around Flash has accepted that their lives have changed but chooses to ignore how, only Caitlin hides the fact that the powers of Killer Frost are manifested in her.
Wells and Jesse return from Earth-II with great news: Jesse has acquired racing powers and wants to become the vigilante of his universe, a decision her father would like her to be dissuaded.
For his part, Wally handles the news badly, because he did not have any powers while he went through the same events. At the same time, a new meta-human appears in Central City: Magenta, the alter ego of Frankie Kane, an orphan who can control metal thanks to Dr. Alchemy.
Barry continues to oversee Jesse's training when a new meta-human appears: Sam Scudder, a burglar capable of crossing mirrors in search of his former partner, Leonard Snart. Unease sets in between Barry and Joe now that the two people he raised as children are dating.
Caitlin leaves STAR Labs to find her mother, a brilliant scientist expert in cryogenics who could help her harness her increasingly powerful and uncontrollable powers. Barry tries to keep his job as a lab technician for the police, against Julian Albert's advice, but Central City needs the Flash against a giant monster who inexplicably appears on the streets.
Wally commence à avoir des rêves le montrant en Kid Flash, un signe que le Dr Alchemy s'intéresse à lui désormais. Mais un autre méta-humain né du Flashpoint apparait en ville et occupe Flash. Caitlin sent ses pouvoirs la dépasser et se prépare à partir à tout moment.
Barry has discovered that behind Dr. Alchemy is Savitar, god of speed and master of swift strength. To save him, Caitlin must use her freezing powers, freeing Killer Frost a bit more. She goes in search of Dr. Alchemy to free herself from his powers, questioning Barry's choices and the consequences for those around him.
As they seek to find Dr. Alchemy and Savitar while wondering about Wally's new racing powers, Barry and his entourage see an alien ship arrive in the middle of Central City. ARGUS already knows the invaders, the Dominators and Lyla suspects a major attack. To respond to the attack, Barry decides to call in all possible reinforcements: Green Arrow and his allies, Legends of the Waverider and Supergirl, whom he encountered during his brief stint in a parallel land. But the secrecy of Flashpoint will complicate the team's common confidence.
Christmas is approaching but the threat of Dr Alchemy and Savitar is still hanging over and Barry's entourage does not have the heart to party. To fight the god of speed, Barry travels to Earth-III to find Jay Garrick. His research leads him to believe that Julian might know more than he says. H. R. oversees the training of Wally, who also wants to fight Savitar.
Barry is still tormented by his glimpse of the future. When a criminal appears in Central City and foreshadows that Iris's death is inevitable, he searches for all possible means to change the future, while Wally, who takes his first steps in the Kid Flash costume, suffers. Meanwhile Caitlin asks Julian for help in sorting out the issue of his growing power.
Barry is looking for a way to increase his speed to be ready to face Savitar when the time comes. An Earth-19 envoy, Gypsy, comes to retrieve H.R. and bring him back to his home world, but when he learns that he will be condemned to death, Cisco decides to challenge her to a duel. Knowing the moment of her death, Iris embarks on dangerous investigations and takes Wally on board with her.
Barry is personally responsible for training Wally and teaching him all the feats he can do at high speed, such as phasing through matter. A meta-human appears in Central City, capable of causing accelerated aging of matter, and his targets are linked to Flashpoint.
Jesse Quick returns from Earth-2 with disturbing news: Harrison Wells is being held prisoner in Gorilla City and according to Grodd, the gorillas are threatening to set Earth-1 on fire and blood. Caitlin, Julian, Cisco and Barry then go to Earth-II to free their friend. But Grodd had it all planned.
Gypsy bursts into the labs of Star Labs, under Grodd's control. Barry then sees another event that he saw in the future come true: the gorillas of Earth-II are going to attack Central City. As he prepares for the assault, Jesse decides to stay on Earth-I, a decision that Harrison Wells welcomes surprisingly well.
Wally continues to push his limits to be ready on the day of Savitar's attack, which is where the God of Speed begins to appear to him and torment him. Barry is determined to stop Savitar but his choices are questioned when he hides his motives.
To free Wally from Pure Speed, Barry returns to the heart of the source of his power and dangers, then comes face to face with an enemy he believed to have disappeared. Jesse Quick decides to take the lead against Savitar using the claw he left behind to find him.
J'onn J'onzz and Mon-El come to Earth-I with Supergirl in a coma induced by Music Meister, a being with strange powers. He manages to surprise Barry and plunges him into the same state as Supergirl. The two heroes regain consciousness in a film set from the 1930s, without powers, where the Music Meister gives them only one instruction: to get out of this trap, they will have to follow the script.
A new meta-human appears in Central City, Abra Kadabra, with powers close to magic. Gypsy wants to bring him back to Earth-19 but when he claims to know some valuable information about Savitar, Barry is reluctant to let him go. The disagreement will have serious consequences.
Killer Frost has been released and will start cracking down on Central City. This is the moment when Barry chooses to take a big risk: to go to the future in 2024, to find his partners after the fight against Savitar and to obtain the missing information to save Iris. But during those eight years Barry has given up on the fight, the Flash team has disbanded, and Central City is in the hands of Mirror Master and Top.
According to Barry in the future, the only person able to trap Savitar in Pure Speed is Tracy Brand, who will not complete her work until four years after Iris' intended death. Killer Frost is already chasing the scientist, and Julian notices that Cisco is reluctant to use his powers to stop his friend.
Barry now knows that beneath Savitar's armor hides a temporal double born from the paradoxes of Flashpoint and his own coming fight against Savitar. Cisco then has the idea to prevent Barry from remembering the events to come to gain the upper hand but causes total amnesia in Barry, as well as in Savitar. To cure him, Killer Frost offers to help.
Cisco has found what could fuel Tracy Brand's cannon to counter Savitar: a Dominator relic kept at the ARGUS premises. Lyla refusing to give it to Barry, he decides to travel through time in order to ally himself with the best burglar he knows, Leonard Snart alias Captain Cold. As they infiltrate the Argus premises, Snart and Barry are surprised to find King Shark, used as a keeper for the relic.
With the sacrifice of H.R. who took Iris's place, Savitar sees his own existence on the verge of being erased. However, he has already foreseen this eventuality with a plan B after having removed Vibe with the complicity of Killer Frost: he wants Cisco to modify the Speed Force Bazooka to make it multiply through the ages, thus allowing it not to be erased from reality and become a god.