The Flash’s life has been defined by one date, March 19, 2000, a night in which the Reverse-Flash traveled back in time and murdered Barry’s mother. This event created a domino effect in The Flash’s life, which started with his father being framed for her murder.

As the series gears up to reach the finish line in its nine-year race, Barry is forced to revisit the worst day of his life one last time in part one of the four-part series finale.

Although the series has shown Barry revisit this moment multiple times before, this time he is able to receive the closure he has been chasing for most of his life.

In the final story, titled “A New World,” The Flash and his archenemy, Eobard Thawne, also known as “Reverse-Flash” engage in their last showdown.

The episode takes place nine months after Oliver Queen returned to help Team Flash save the multiverse. Iris is nearly ready to give birth to her and Barry’s daughter.

While Iris finds out she won a Pulitzer Prize for her article on the Red Death , Barry disappears right in front of her. He predicted Iris’ article back in the season premiere.

Unbeknownst to Iris, Barry was whisked away to the year 2000. He tries to tap into the Speed Force and return to his own timeline but fails .

Barry visits the Central City Police Department and meets a younger version of David Singh and Joe West, where they areearly into their law enforcement careers. As Barry speaks with Joe to locate a scientist who could aid him, he realizes he has arrived on the dreadful date on which the Reverse-Flash murdered his mother.

When Barry tries to approach his parents on the streets of Central City, he is attacked by the Reverse-Flash and taken to a hospital under Henry’s care.

Using the name of his future son as an alias, Barry is treated to lunch by his parents but leaves suddenly to confront Reverse-Flash, who mocks him but denies being the one who sent Barry back in time.

Barry realizes this version of Reverse-Flash is the original , whose main goal was to kill young Barry but took his mother instead. He carefully denies telling Eobard Thawne how the future event will unfold.

Meanwhile, Joe and Singh investigate the site where Barry was attacked, and Joe finds a mysterious gem that possesses him.

After saying farewell to his parents one last time, Barry is confronted by the possessed Joe West. The entity identifies himself as the personified Negative Speed Force , who claims to be ready to restore balance after Barry destroyed it at the end of season eight.

The Negative Speed Force easily beats Barry and points out that killing him would restore the balance caused by Thawne’s death later in history. Barry manages to extract the Negative Speed Force from Joe without hurting him and the troubling crystal disappears.

Barry gets back to his family home early enough to face the Reverse-Flash and fight him. He saves his younger version, which prompts Reverse-Flash to kill Barry’s mother, allowing fans to reach a full circle in the series.

In the aftermath of the moment, Barry expresses gratitude to Thawne for allowing him to see his parents one last time and give him closure. He leaves Thawne to his fate before he is whisked to another point in history.

In the episode’s post-credit scene,  a new timeline with a scientist named Malcom Gilmore, who bears a strong resemblance to Eddie Thawne, is revealed.

Gilmore experiences a similar accident to Barry that gave him his super speed before discovering a case file about Eddie’s death from an alternate reality, raising even more questions as “The Flash” races towards the final three episodes.