"Flash" season 3 will be titled "Flashpoint," and its new trailer teases what Barry's alternate universe will look like.

Since "Flash" was spun off from "Arrow," it has provided viewers hints that it will eventually adapt Geoff Johns' "Flashpoint" comic book series. While nothing was certain at first, the "Flash" season 2 finale seemed to have confirmed the speculations.

In the season 2 finale, Barry defeated Zoom through the help of his friends. However, Barry decided during the final moments of the season to go back in time to save his mother. This event seemed to have set up "Flashpoint," which focuses on an alternate universe that was created when Barry went back in time to save his mother.

The "Flash" 3 video teaser that was unveiled during "The Flash" panel at Comic-Con San Diego recaps the final moments of the season 2 finale, and then offers a glimpse of what is to come. The video shows the notable differences in the alternate universe of Barry--his parents are alive, Joe and Iris West do not recognize him anymore, Cisco Roman is the founder of Ramon Industries, and Wally West is Kid Flash.

The season 3 trailer also shows the arrival of Dr. Alchemy, who will be one of the big bads next season, along with another unnamed speedster. Its final sequence gives a look back at the many events over the course of "The Flash" 1 and 2, some of which have to do with the characters who are now in "Legends of Tomorrow."

"The Flash" season 3 premieres on October 4, 8:00 P.M. on The CW.