Flash (CW)'s History
After witnessing his mother's supernatural murder, Barry Allen is taken in by Detective Joe West and his family. Barry becomes a brilliant but socially awkward crime scene investigator for the Central City Police Department. A particle accelerator malfunctions, bathing the city center with a radiation during a thunderstorm, and Barry is struck by lightning. Awakening after a coma, he discovers he can move at superhuman speeds. Harrison Wells, the accelerator's designer, describes Barry's nature as "metahuman". Barry vows to use his gifts to protect Central City. As the Flash, Barry also pursues his mother's murderer, the Reverse-Flash.
In the second season, after a singularity event, the Flash is recognized as Central City's hero. However, the event brings a new threat from a parallel earth: Zoom, a demonic speedster who seeks to eliminate all speedsters throughout the multiverse. Harrison Wells' parallel universe counterpart nicknamed "Harry", and his daughter Jesse, work to help Barry stop Zoom and explore the multiverse. Joe and his daughter, Iris, struggle with the arrival of Iris's brother Wally West. After Zoom kills Barry's father, Barry travels back in time to save his mother's life.
By changing his past, Barry alters the timeline, resulting in "Flashpoint". Though he is somewhat able to restore the timeline, this creates new threats, including Savitar. After Harry and Jesse return to Earth-2, another Wells doppelgänger is recruited: the novelist "H.R." Wells. Both Wally and Caitlin Snow begin to manifest metahuman abilities; Wally suits up as the speedster Kid Flash, while Caitlin is forced to suppress her ice-powers to prevent becoming Killer Frost. When Barry accidentally travels to the future and sees Iris killed by Savitar, he is desperate to change the future to prevent that from happening. After saving Iris and defeating Savitar, Barry takes his place in the Speed Force.
In the months since Barry left, Wally and Cisco have barely been able to protect Central City. When a new foe defeats them easily, requesting a battle against the Flash, the team decides to bring Barry back. While they manage to do so, Barry's return releases dark matter, turning a dozen people on a city bus into metahumans. One of these metahumans is private detective Ralph Dibny, who joins the Flash's team. While Barry and Iris prepare for their wedding, the team realize that Barry's arrival and the creation of the bus metahumans were orchestrated by the Thinker.