The Flash season 2 ended with Barry Allen finally defeating Zoom, and saving the multiverse. The episode featured several revelations, but the shocking moment came at the very end when Barry decided to run back in time and save his mother, Nora Allen, from the Reverse Flash, thereby erasing the whole timeline.
Episode 23 titled The Race Of His Life, featured Henry's funeral as Barry vowed to kill the person responsible for his father's death. Barry, who was mourning for his father, is challenged to a race, by Zoom, which was a part of his elaborate plan. Zoom wanted Barry to race so he could power a weapon that could destroy the multiverse.
To motivate Barry, Zoom even kidnapped Joe, thereby setting a stage for a final race between the two speedsters. Barry outsmarted Zoom by bringing another Flash from the remnants of Time as Time wraiths followed. The weird creatures snatched Zoom up and sucked the life right back out of him before carrying him away. So, Zoom is gone and Barry saved the day.
The episode also revealed the person behind the Iron Mask, which turned out to be Henry Allen's doppelganger, Jay Garrick, from Earth 3. The real Jay Garrick decided to leave for his Earth, as Harrison Wells and Jesse too decided to leave for Earth-2.
The chapter also featured a Barry and Iris moment, where they declared their love for each other and shared a kiss. Barry, however, asked for some time away to deal with his issues.
Iris to Barry: You waited for me for years, you let me get to a place where this was possible, so I am telling you, I am going to do the same thing for you. Where ever you need to go, whatever you need to do, do it, When you get back, I will be here.
The shocking moment came at the end as Barry raced back to the night that his mother was murdered by Reverse Flash. Barry jumped into the fight and stopped Eobard Thawne from killing Nora. The episode ended on a cliffhanger with Barry spotting his Time remnant from the last time he jumped through the continuum (In season 1 finale) and watched his earlier self disappear.
Barry's decision to save his mother will have a big change in the timeline as the Speedster has now changed the moment that would eventually lead him to become The Flash. The plotline looks similar to the comic book storyline called Flashpoint written by Geoff Johns. In the Flashpoint comics, Barry saves his mother but the consequences are beyond disastrous. When The Flash season 3 returns this fall, Barry Allen will have to face the consequences of his decision.
Kevin Smith, who recently directed an episode on The Flash, hinted about a possible "Flashpoint Paradox" plotlinefor season 3. He wrote on Twitter, "And the Flashpoint Paradox has begun! Great close to @CW_TheFlash Season 2! Reveal of the man in the iron mask was just warm and wonderful."
Previously, Grant Gustin who plays Barry also teased a vulnerable timeline going into season 3. He had said, "Barry makes a decision at the end of this season that obviously he'll be vulnerable going into season 3, but, I think because of some stuff that goes down, the timeline will also be vulnerable going into season 3. I think regardless of what happened, this will affect every other relationship in Barry's life."
The Flash will return with season 3 in fall.