We open up 15 years ago and revisit the night Barry’s mom died and how he was taken into the loving West family. Many years ago on Earth 2, we see Hunter Zolomon awoken by his parents arguing. Hunter’s abusive dad, James, is dressed like the Jay Garrick Flash and just before he kills his mom in fronto of his eyes, gives him his helmet. In the aftermath, Hunter is sent to an orphanage as no other family wanted him.
In the present, the Flash is in Keystone City to test the tachyon device that he places on his chest. The Flash starts to run really fast where he disappears for a moment only to reappears seconds later. When Barry goes to STAR Labs, he wonders how long he was away for. We know in that moment, Barry went to National City to help Supergirl.
Caitlin and Cisco tell him that Barry has run four time faster than ever before. Harry notes that it is even faster than Zoom. Barry asks Harry to make a smaller version of the tachyon device, which he does making it similar to the device he developed to take his speed hidden under his emblem. Barry then wants to open up a breach to go back to Earth 2 to confront Zoom. Harry refuses to help as he doesn’t want to endanger his daughter.
At the West’s, Joe is against Barry going back to Earth 2. When Wally comes over to do laundry, we learn he is no longer living on campus as he can’t afford to. Joe tries to give Wally money but he refuses. Later Joe seeks Barry’s advice on how he can get Wally to let him help. Barry tells Joe that Wally doesn’t want money but wants to move in. Joe then offers Wally a room in the West household and he happily accepts, calling Joe dad for the first time.
Barry gets an idea on how to open up a breach when Joe makes a passing comment about Wally’s doppleganger. Barry wants Cisco to tap into Reverb’s ability to open up breaches. Cisco tries in the breach that was in STAR Labs but to no avail.
Harry goes to visit Wells to see if he has found Jesse, which he has not yet. Joe then advises Harry to help Barry open up a portal to Earth-2 as the two of them together have a better chance to succeed in taking down Zoom.
Barry then take Cisco to an abandoned hospital were a breach signal was the strongest. Cisco tries again but still can’t open a breach. Harry arrives and gives him the Vibe glasses that he has tinkered with. Cisco puts them on and starts to open a breach. Zoom on Earth-2 senses this and goes to the hospital encouraging Cisco to continue but he stops and refuses to open up a breach again. Back at STAR Labs, Cisco confides in Barry that he is afraid that if he can tap into this power, he will turn to the dark side and become the evil Reverb. Barry assures Cisco he won’t as he has the Flash family behind him to support him. With Cisco being able to open up different multiverses this definitely opens up the possibility of Supergirl being able to come to Central City or even Star City for a cross over next season. Let’s make that happen!
Also at STAR Labs, Iris confides in Caitlin that she couldn’t go on a date with her editor. Caitlin sees Iris is developing feelings for Barry. Iris doesn’t know what to feel as on Earth-2 they are married and in future they get married. Signs are pointing that they are meant to be together and wonders if she should believe in destiny. Caitlin says she should.
When Harry hears Jay’s real name is Hunter Zolomon, he tells Team Flash that on Earth-2 Hunter was a serial killer who killed 23 people. Hunter’s past was similar to Barry’s but he ended up in the foster care system. Hunter ended up in a mental hospital and undergoing electro shock therpay the night of the particle accelerator explosion that gave him his speed. Knowing Zoom’s origin story, Barry believes they have an advantage over him.
Harry. Joe, Caitlin and Iris are safe in time vault as Cisco and Barry open the breach in the mental hospital. Zoom comes in and says they shouldn’t have opened up the breach. The Flash and Zoom race around Central City. When it looks like Zoom is going to catch the Flash, the mini tachyon in the suit turn on and he gets ahead of Zoom and heads for STAR Labs. Once there, Zoom notes the Flash got faster and looks forward to taking it. There is a chase around STAR Labs but zoom is stopped when he sees cardboard cutouts of his parents. The Flash shots a restraining device on Zoom’s legs to trap him. Barry says Zoom mistake was telling Caitlin about his doppelgänger.. Hunter calls Caitlin a smart girl and did so to get her to stop fixing him. Zoom notes he doesn’t care how many people he hurts and says he and Barry are the same and he could have been evil. Zoom then uses vibrations to break free of his restraints and escapes.
Barry, Iris and Joe come home to see the place trashed and Wally gone. There is a note from Zoom that he will exchange Wally for his speed. Zoom has taken Wally to Earth-2 and is in the cell that Jesse once occupied. Wally sees the Man in the Iron Mask. Zoom arrives and says the Flash is the only one that can save him, Wally doesn’t understand why the Flash would save a stranger. Zoom notes the Flash cares about someone that cares for Wally.
Back at the West’s, Team Flash is debating how they can get Wally back without Barry trading his speed. Joe needs a moment and in Wally’s room, Barry comes in. Joe doesn’t want Barry to give his speed to Zoom but just wants his son back. Barry knows the only way to get Wally back is to give Zoom what he wants.
The exchange happens and Wally is safe. As preparations are made to take Barry’s speed, Zoom explains how he killed himself. Zoom traveled back in time to take a past version of himself. Zoom easily convinced his time remnant of his plan. Zoom also tells Team Flash that it was fun to dress up like a hero to give people hope and to have it ripped away. Caitlin calls Zoom a monster and he flashsed back to night of his mom’s murder where she called her husband a monster.
Barry goes on the treadmill and starts to run. Soon, his speed force leaves his body and Barry is human again. Zoom then immediately injects himself with Barry’s speed and then goes to kill Barry. Caitlin intervenes and begs Zoom not to. If Zoom felt anything for her then he will stop. Zoom does stop but takes Caitlin captive.