When Barry went back in time to prevent his mother's murder, he didn't just save her from Reverse Flash -- he created a whole new timeline. In a new trailer for "The Flash" Season 3, Barry approaches Cisco for help in correcting the "Flashpoint" timeline and explains exactly how he managed to create "a whole new existence."

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Starring Grant Gustin, Jesse L. Martin, Carlos Valdes and more, "The Flash" returns to The CW on October 4 at 8 pm EST.