- "Smart enough to figure out who Harrison Wells really is, you see I know his secret."
- —Hartley reveals he knows something about Wells
Dr. Wells' former protégée, Hartley Rathaway, returns to seek revenge on his mentor after being affected by the particle accelerator explosion. Now able to manipulate sound waves, the brilliant Rathaway is a dangerous threat to both Wells and The Flash. Meanwhile, Iris is thrilled when she's hired by the Central City Picture News as their newest cub reporter. Unfortunately, her editor pairs her with a veteran reporter, Mason Bridge, who wants nothing to do with her. Cisco recalls his first day on the job at S.T.A.R. Labs when he met Hartley and Caitlin. Joe asks Eddie for a favor but asks him to keep it a secret from Barry. 
The flash is talked through capturing multiple men by Wells. After he returns to Star Labs, Barry and the team take a photo together. Barry then heads home and learns Iris was over Joe's home. Iris says that she had forgot things. Joe invites Iris to dinner but Iris turns it down and then learns that she received a call from the paper. She then learns that she has a job at the Central City paper.
Harrison heads home and once the door is closed, stands up from his chair. He begins to walk, showing that yet again he is hiding something. A little later, he has a fire going and music going as he sips wine. His cell goes off and he answers it. No one picks it up at first until a voice says, "We both know what you did," before all the glass on his house break. He speeds away.
The next morning Barry and Joe show up and Harrison is back in his chair. He apologizes to them and he makes up a reason for the accident. Caitlin and Cisco show up and tell Barry that they had never been to Wells' home.
Two years before, Wells is playing chess with a man when Cisco knocks on the window. The man is Hartley and he isn't too happy to meet Cisco due to his wardrobe choices. Hartley is jealous.
Eddie walks over to Joe and they talk about how something didn't add up since Harrison couldn't walk. Barry uses his powers to fix the windows to find the point of impact. Harrison tells Barry that he already knew who did this. Later in Star Labs, Harrison explains who Hartley is and how they had a disagreement a year before. Barry and Joe headed out. In the past, Cisco and Hartley walk around when they met up with Caitlin who is on her way out to meet Ronnie. Hartley believes that Cisco will only last a week.
Iris heads to her first day at the job and she sits down next to Mason. The editor walks in and Iris learns that the editor only wants her to cover the Flash.
Barry is in his lab with Joe talking about how the glass had to break. Eddie then enters and tells them about Hartley heading to his family's company. The cops show up and Hartley is destroying windows. The flash then shows up Hartley threatens Caitlin, Cisco, and Harrison. Hartley mentions knowing Harrison's secret. Hartley is then brought to Star Labs and mentions his name as the pied piper. When they lock up Harley, he insults both Caitlin and Cisco until Harrison shows up. Harrison tells him he didn't want him to turn out like he did. Hartley however knows that Harrison is saying it for Barry's benefit. Harrison then learns that Hartley mentioned him having a secret. Harrison tells them that his secret was that he knew that the particle explosion had a chance of exploding ahead of time. He then apologized to Caitlin and Cisco. Caitlin tells him she expects a heads up next time before leaving, along with Cisco. Barry then says that the duo who left stayed by his side and that they needed more of an apology. Barry then says that he broke their trust before leaving.
Iris is at work and tries to talk to her editor and learns that she is only there due her flash connection.
After work, she heads to Jitters to meet Barry. She tells him about her day and Barry just says that people they admire differ in real life. Barry believes in her, something she likes.
Cisco and Caitlin are looking through Hartley's things when they realize that Hartley wanted to be caught. He then escaped. Harrison was in his secret room standing when they learn of the breach. Hartley removes stuff from his ear and explodes a bomb, freeing himself. He then heads to Caitlin and knocks her out. He takes back his stuff and goes on the computer as Harrison lost his strength. He then calls Barry and so Barry heads out, leaving Iris alone. Harrison is on the floor when Hartley finds him. However when Barry shows up to Harrison, he is in a chair and Hartley is gone. Cisco had a concussion.
In the past Harrison and Hartley met up by and Hartley brings up the issues. However Harrison fires him and threatens him before sending him away.
In the police station, Iris and Mason show up to the press conference. Harrison begins to talk about the explosion, as Hartley uploads files that he had taken from Star Labs. Harrison apologizes on tv for what happened. When Mason asks a question, Harrison ignores it and answers it when Iris asks the same. Mason is surprised when Iris's gumption.
With Cisco wanting something to prove, Harrison approached and told Cisco how his heart added to the work experience there. He says how there was no second or first favorite.
Hartley then hacks into Star Labs and talks to them as if it was the game of chess. Hartley admits to planning to take out pawns while waiting for the Flash. Upon learning where Hartley is, Barry rushes off and manages to save a woman from a falling car. Cisco admits that due to Hartley stealing his scans, he could harm the flash. As it is, Harrison hacks a frequency to harm Hartley's weapons to save the flash. It destroys Hartley's gloves, upseting him. Barry gets up and sees Hartley is on the ground.
Cisco, Barry, and Caitlin talk about how Barry is doing. Cisco then decides to lay down and Caitlin follows, leaving Harrison and Barry alone. Harrison tells Barry that he wants to restore his trust and Barry says that it was today. He then gives him a copy of the photo they took.
Barry speeds off and heads to talk to Joe. Barry tells Joe that it couldn't have been easy taking care of him growing up since he had been in science. He tells Joe that no one could replace him, not even Wells. Eddie walks up and tells Joe that there was nothing. Eddie asks if Joe is sure about looking into Wells.
Hartley wakes up and learns that he is locked up. Hartley then mentions knowing about Ronnie and how to save him.
In his hidden room, Harrison is trying to keep the device that he had stolen to keep his speed. However it wasn't working.
|The Flash season 1|
|"Pilot" • "Fastest Man Alive" • "Things You Can't Outrun" • "Going Rogue" • "Plastique" • "The Flash Is Born" • "Power Outage" • "Flash vs. Arrow" • "The Man in the Yellow Suit" • "Revenge of the Rogues" • "The Sound and the Fury" • "Crazy for You" • "The Nuclear Man" • "Fallout" • "Out of Time" • "Rogue Time" • "Tricksters" • "All Star Team Up" • "Who is Harrison Wells?" • "The Trap" • "Grodd Lives" • "Rogue Air" • "Fast Enough"|