Events after the Justice League, Barry has been having a new life with Iris, as he tries to meet with his nephew-in-law, Wally West, but may face problems with Heat-Wave and the new Mirror Master.
- Barry Allen/Flash (Bradley Cooper) - now married to Iris and has trouble hanging with Wally, and realizes Wally just got struck by an accident, in the end, takes Wally to take out Captain Cold.
- Wally West/Kid Flash (Charlie Hunnam) - Iris's fast-food eating nephew, who cheated at Coast City University, and was expelled to live with Barry and Iris, then he got strucked with the same accident Barry got into, and became Kid Flash, in the end, takes his mantle by heart.
- Iris West (Jessica Chastain) - Barry's newfound wife after the events in "Justice League", as she witnessed district attorney and former colleague, Mick Rory trying to win her, in the end, she becomes pregnant.
- Rudolph West (Kevin Dunn) - Wally's father, in the end, is seen talking to Sam Scudder about Heatwave.
- Mary West (Julie White) - Wally's mother, in the end, is seen making cookies for Barry and Wally.
- Evan McCulloch/Mirror Master (Simon Pegg) - gets tired of the criminal life after passing the mantle to Sam Scudder, in this version, he hates his criminal life and was the first Mirror Master, instead of the second, in the end, is seen making an announcement about the Heat-Wave incident.
- Mick Rory/Heat-Wave (Guy Pearce) - the main antagonist and district attorney to Central City Police Department, he inspires Harvey Dent in this version, he uses flaming powers in his body, he has the same humor as Aldrich Killian, his goal is to destroy all of Keystone City, in the end, Was destroyed by his own device.
- Sam Scudder/Mirror Master II (Jeff Bridges) - the secondary antagonist, he is Mick's father figure in this version and the second Mirror Master instead of the first, in the end, was arrested by the police department.