After emerging from a coma, Barry discovers that he has superpowers and puts them to the test. However, he soon goes up against another metahuman created by the same accident that gave him his abilities.
Iris is escorted by Barry to a university gathering, honoring Simon Stagg, a famous scientist. When six gunmen interrupt proceedings, Barry changes into the Flash only to pass out. While the scientists try to discover what's wrong with Barry, they realize that they're dealing with a metahuman who can replicate himself. Meanwhile, Iris becomes intrigued by the mysterious red streak fighting crime in Central City.
Barry and his friends have to figure out a way to defeat an untouchable opponent when an executed prisoner comes back with the power to transform himself into lethal gas. Meanwhile, Joe goes to see Henry for the first time in years, and Eddie is frustrated that Iris won't tell her father that they're dating.
The Flash goes up against a robber who has acquired a cold gun capable of putting the speedster on ice. However, the hero is shocked when he discovers that Cisco was the one who created the gun, as a weapon of last resort. Meanwhile, Felicity comes to Central City to see how Barry is doing.
A thief blows up a floor of an office building stealing a government file, and General Wade Eiling arrives in Central City to oversee the investigation. Harrison has a history with Eiling and warns the team not to trust him, and they soon discover that the thief is a metahuman... and Eiling wants her as a weapon. Meanwhile, the Flash meets with Iris to try to convince her to stop blogging about him.
The newest metahuman to hit Central City is Tony Woodward, who can transform into super-strong metal. The Flash discovers that his speed is useless against his armor-plated antagonist... unless he runs faster than he ever has before. Meanwhile, Joe questions Harrison about his possible involvement in Nora's death, and Iris puts herself at risk blogging about the Streak.
While battling a metahuman who feeds on energy, the Flash loses his powers. The scientists try to restore Barry's powers, just as the same metahuman arrives at S.T.A.R. Labs eager for revenge on Harrison. Meanwhile, Iris and Joe find themselves in a hostage situation when Arrow villain Clock King takes over the police station.
The Arrow and his team come to Central City to identify a boomerang used in a murder. However, they soon end up helping the Flash when he goes up against a metahuman who can drive his victims into fits of rage.... and the speedster is his next target. Meanwhile Iris finds herself caught between her boyfriend and her idol when Eddie tries to create a task force to bring down the Flash.
The man who killed Nora Allen finally confronts the Flash, and soon reveals that he's the hero's superior in every way. Meanwhile, Barry confesses a secret to Iris, Eddie asks Iris to move in with him, and Caitlin discovers that Ronnie is alive... but different.
While Barry strives to become fast enough to defeat Reverse-Flash, Captain Cold returns to Central City with a partner and takes Caitlin hostage to force a confrontation with the Flash.
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.