“Potential Energy” is episode ten of season two of The Flash.
Barry runs to meet Patty at a restaurant carrying a bunch of roses. Which turn out to be quite flammable and need stamping out on the floor. Then Zoom shows up and takes Patty to the top of a building and holds her over the edge. When Barry arrives, Zoom taunts him then drops Patty. Then Barry wakes up in bed next to Patty; it was just a dream. Well, nightmare.
Joe and Iris are showing Wally, Joe’s son and Iris’ brother, around the precinct. Joe is being a bit obvious in what he is saying as Iris points out. Then someone in cuffs calls out to Wally, saying where are your cuffs taillights. Which Wally brushes off, saying that he has one of those faces. Joe invites Wally around for dinner that night and, after Wally leaves, Patty shows up and asks if she can have a chat. Joe says yes, but it’s actually Iris Patty wants to talk to. So Iris tells Joe he’s not needed.
Patty wants to talk to Iris about Barry. She wants to figure him out and Iris tells her that would make her the first. Patty says that Barry is, not distant – guarded is what Iris suggests. Iris tells Patty that Barry carries the weight of the world on his shoulders, even when he doesn’t have to. Patty says Barry doesn’t need to do it with her and Iris suggests she tell Barry that.
Wells is working on some equations which clearly aren’t going well, so he knocks some things on the floor. Cisco arrives and complains about that, saying that you can’t just throw someone else’s stuff around just because you’re pissed. So Wells knocks some of his own things on the floor. Which makes Cisco happy.
Cisco inquires as to what Wells is doing, and Wells responds that he’s getting the wrong answers, Cisco suggests he’s asking the wrong questions. Instead of trying to make Barry faster, they should see if they can make Zoom slower. Wells points out that they tried that in “Enter Zoom” and the serum failed, only annoying Zoom. Cisco has another suggestion though – the Turtle.
The Turtle is Cisco’s name for a meta-human he’s been trying to track down (which, it seems, everyone but Barry knows about; when Barry asks why Cisco hasn’t mentioned the Turtle, Cisco responds that they have been a little busy). A number of robberies were carried out at what looked like high speed. Just like the Flash. People had an item one second and it was gone the next. Cisco has a video of one of these robberies and it shows a man walking around talking items whilst everyone is standing still. The Turtle is apparently not stopping time, just slowing down everyone around him. Cisco thinks that this could help slow Zoom down.
The question is how to find the Turtle. All the items stolen were of immense personal value and were generally classed as lost not stolen by the police. There’s a press conference being held at the CCPD about some recovered diamonds, with their owner, and Barry heads there. At the conference, the Turtle appears and steals one of the items, a ring. He manages to slow Barry down too. Not stop him completely, but slow enough that the Turtle can easily get away. Which he does, winking at Barry. It seems that the Turtle is removing the surrounding kinetic energy into himself, meaning they only have potential energy. Barry moves faster than anyone else, so the Turtle couldn’t completely stop him.
Barry is wondering what to do about Patty and Iris tells him to tell Patty the truth. So he decides to and informs the others of his decision – as he has just invited his girlfriend on a sting to catch the Turtle. However, Wells warns Barry not to tell her, for if Zoom finds out Barry cares about Patty, Zoom will take her from him.
There are problems with Wally, who has just been introduced to his father and sister for the first time and he’s also, as could be guessed from the comment at the precinct, involved in something that is not exactly on the straight and narrow. Patty is also coming to some personal decisions. Caitlin decides to try and see if they can get Jay’s speed back, which has an unforeseen outcome.
In the previous episode, “Running to Stand Still”, Wells told Zoom he had worked out why Zoom was sending meta-humans against Barry. Zoom wants Barry to get faster, so that there is more speed for Zoom to take. And Wells agreed to help Zoom steal Barry’s speed in exchange for his daughter’s life. Wells might prefer to stop Zoom, but if there is no certain way of doing that, what will he do?
The post-logo scene has a heck of a surprise.