A laboratory accident endows a police scientist with the ability to move at superhuman speed which he uses to battle a menacing gang as a superhero.
Homeless people are dying and their bodies are disappearing. Tina rekindles a relationship with a former colleague who is an expert in genetic engineering.
The corrupt District Attorney Thomas Castillo hires a private eye named Megan Lockhart to find out the Flash's identity. He then blackmails Barry to work for him, or he'll expose his secret.
While arranging security at the Central City Museum, Barry is reunited with an old girlfriend and a former mentor.
Someone spreads graffiti, and messages asking to meet "Flash" at a church. Barry goes to the church. Shortly after that, he begins to experience black outs and memory losses.
A bank robber escapes from prison. He goes back to Central City to get his money and revenge on the cop who busted him, Henry Allen, Barry's father.
An orphan boy has information that incriminates a 1960s cult figure who is trying to make a comeback.
Pieces of a broken medallion are the only clue to an unknown assassin who is on a deadly rampage in central city.
Barry befriends an African American who was once a super hero that defeated a terrorist called the Ghost, who blackmailed the city through television sets. When the presumed dead criminal is defrosted, the Night Shade is back in business.
An invisible man gets into Star Labs, and releases a neurotoxin with Tina inside the lab. Then he starts killing scientists who worked on the project. Flash must find the invisible man and save his friend.
A jazz musician friend of Julio's is about to be executed. An hour before the execution, a friend calls and says he has evidence that could exonerate their friend. Before Barry can contact him, he disappears. They have less than an hour to save a condemned man.
Barry must protect his old girlfriend, Megan Lockhart, from an obsessed, maniacal criminal disguised as The Trickster.
Barry is having trouble sleeping. Tina tries to use bio-feedback to help him, but it back fires on Tina. She joins a gang, and she's able to hold Flash at bay with her knowledge of his strengths and weaknesses. Barry has got to find a way to save his friend.
Barry tries to help a young woman. She found out about her husband's criminal life, and is trying to escape from him. She takes their daughter with her, but he wants them back.
Jay's killer, Nicholus Pike, is released from jail and blames the Flash for Jay's death. He sets the Flash up by using a heat seeking bomb on him, but something goes awry. Instead of killing the Flash, it sends him into the future where Pike is in charge and outlaws anyone from mentioning the Flash.
There's a new vigilante in town, the Deadly Nightshade, who fights crime by killing criminals. The Flash and the original Nightshade team up to take him down.
Captain Cold, who freezes his victims to death, is contracted to kill the Flash.
A scientist and his business partner are trying to develop a being with super speed, their attempts fail. They manage to clone the Flash. Their creation learns quickly, but is emotional moral equivalent of a child. Barry must stop his twin.
A battery is stolen by a criminal calling himself the Mirror Master. He soon steals a crystal from Star Labs. Tina will get fired if they can't recover the crystal. Tina's mother comes for a visit, and an old friend of Barry's also stirs up trouble.
A small time crook gets a hold of a device that puts people to sleep. He goes on a spree while the people are unconscious. He has a plan to knock out the entire city, it's up to the Flash to stop him.
An android built by the government to use an assassin refuses to obey her orders. She escapes, and is befriended by Tina and Barry.
With the help of an insane admirer who wants to be his sidekick, the Trickster escapes from police custody and places the Flash under his mind control.