Barry discovers his powers and puts them to the test, only when he finds its no longer a test but the real thing when he encounters a certain someone.

Barry changes into the Flash when six gunmen storm a university event honoring a scientist, but his heroics don't match up to his expectations. Meanwhile, Iris becomes even more intrigued by the "red streak."

The Flash faces a new meta-human named Tony, who can turn himself into girded steel at will.

Barry enjoys the annual tradition of tree trimming and gift exchange with Joe and Iris. He gives Iris a touching gift, but the moment is interrupted by Eddie’s arrival.

While Barry, Harrison, and Caitlin hunt down Ronnie, who has attacked a man, Joe recruits Cisco to help him learn the truth about who murdered Nora Allen.

When a villain calling himself the Trickster runs rampant in Central City, Joe and Barry go to Iron Heights to talk with the original Trickster.

Wells presents Barry with a life-changing choice. Dr. Martin Stein and Ronnie Raymond return to help the S.T.A.R. Labs team with this final fight.

Picking up months after the Singularity attacked Central City, Barry is still struggling to forgive himself for Eddie’s death. Concerned about putting his friends in danger, Barry has pushed everyone away and has chosen to protect the city on his own. When a meta-human named Atom Smasher attacks the city, Iris tells Barry that he needs to let his friends help him protect the citizens of Central City. Meanwhile, Cisco helps Joe with his Meta Task Force.