The Flash season two returns from its midseason break with an episode full of surprises and the arrival of someone who could be a new major player in the second half of the second season. Titled ‘Potential Energy,’ the episode aired on January 19, 2016.
Barry (Grant Gustin) arrives for his date with Patty (Shantel VanSanten) with roses ablaze. Seriously, he sets the roses on fire. Barry’s so happy that he tells Patty it feels like he’s been struck by lightning twice. That’s barely out of his mouth when Zoom zooms in, takes Patty away, and kills her by dropping her off a building. Thankfully, it was all a dream.
Joe (Jesse L. Martin) walks his son Wally (Keiynan Lonsdale) around the police station and Iris (Candice Patton) tells him she’s super happy to have a brother. Wally’s not sold on this whole family thing yet and actually cool to his new family when a crook in handcuffs asks him where his cuffs are. Wally shrugs it off and leaves. In walks Patty and she needs Iris’ advice. Over coffee, she asks for Iris’ help in figuring Barry out. Patty thinks there’s something holding him back, but Iris says it’s because he has a habit of carrying the weight of the world on his shoulders.
Meanwhile at S.T.A.R. Labs, Dr. Wells (Tom Cavanagh) is pissed and tossing things around. Cisco (Carlos Valdes) enters and tells Dr. Wells maybe they can slow down Zoom by stealing his speed and not have to make Barry faster. Cisco has been embroiled in a battle with the Turtle (his white whale), a metahuman who can slow down everything around him as he steals things. They want to catch him and use his powers to slow down Zoom. Barry’s never heard of Turtle but he races away because diamonds have been stolen and a press conference is underway. Barry spots the Turtle stealing a precious ring during the press conference, but Turtle slows him down so he can’t do anything about it.
Cisco wants to know what it was like in Turtle-time and Harrison wants to see how he can use this against Zoom. They figure out who Turtle actually is and Jay (Teddy Sears) is disappointed and feeling lost because he can’t help anyone anymore. But, Caitlin (Danielle Panabaker) is determined to figure out a way that he can.
Joe knows about Turtle and that Cisco’s been chasing him, so he’s happy Barry and the gang have figured out who he is. Joe and Barry talk about their plans for dinner that evening with Wally, and Patty comes in to make sure everything’s okay between them. He asks her out on a romantic date for the following night and she says that’s exactly what they need.
At Joe’s, Wally is a no-show and Iris, Barry, and Joe have wasted an evening waiting or him to show up for dinner. Joe thanks them for being there and heads up to bed. Even Iris knows about Turtle (Barry was definitely the only one not in on this Turtle dude), and she tells Barry that she met with Patty. Barry confesses he’s having nightmares about Zoom killing Patty, and Iris says one day soon Patty will have to learn the truth if he’s serious about being with her. Barry makes up his mind and says he will do it.
At S.T.A.R. Labs, the gang figures out where tTurtle will show up next: the museum. It will happen tonight and Barry calls Patty to ask her to go to the museum with him that evening. Cisco tells him he’s a really great superhero but it’s not a good idea to bring a date to a job, and Barry reveals he’s going to tell Patty the truth. He’s got Cisco’s support, with Cisco telling him Patty’s Team Flash material. As he’s about to leave, Harrison tells him not to do it and to keep her as far away from this as possible because Zoom will take her from him.
At the museum, Barry, Caitlin, and Jay look gorgeous all dressed in formal attire. They’re on the lookout for Turtle while Cisco and Harrison wait outside in the van. Harrison doesn’t like Cisco’s nicknames and explains the backstory behind Zoom’s name. Zoom set a trap and killed 14 officers and left one behind to tell the tale, describing Zoom as blue lightning zooming about. That officer was killed later that night. That’s how Zoom got his nickname.
In walks Patty and she’s stunning. They kiss and Barry takes her onto the dance floor to talk. Barry tells he works hard to hide who he is and he has to really trust someone if they’re going to know the truth. He tells her he trusts her and starts to explain what happened after he was struck by lightning but just then he sees Turtle and breaks off his story, racing away. Turtle figures out it’s a trap and shoots a chandelier hanging directly over Patty’s head. The Flash races to save her but is slowed by Turtle. He manages to push her out of the way just as it crashes to the ground, taking the blow himself. With the lights out, Caitlin and Jay drag him out of the museum.
Back at S.T.A.R. Labs, Caitlin examines him but Barry says he feels fine. Turtle got away with the painting, and Barry has to take off to tell Patty he didn’t ditch her. Jay and Caitlin are left alone and he pours her a glass of champagne. They toast, kiss, and he heads off to help Cisco and Harrison.
Patty’s at home about to open an envelope from Midway City University when Barry knocks on her door. She’s angry and Barry allows her to vent. Patty doesn’t want to just have fun anymore, and she thinks that’s all this apparently has been for Barry.
Wally’s drag racing on the city streets. He wins and gets the other guy’s car, and finally notices Joe has been observing him from the sidelines. Joe confronts him about missing dinner and he wants to know if racing is why Wally actually came to town. Wally is racing to pay for his mom’s hospital bills. Wally says he’s the man of their house and tells Joe to go home to his family.
Patty sips win after Barry leaves. There’s a knock and she assumes it’s Barry again. It’s not, it’s Turtle. She shoots at him but he stops her, grabs her neck and points a gun at her head. She wants to know what he wants and he says, “The thing most precious to The Flash – you.”
Barry returns to Patty’s, sees the spent bullet shells on the ground, and knows something happened. He calls Joe and tells him Turtle has Patty and to meet him at S.T.A.R. Labs.
Turtle has Patty tied up and he tells her he wants her dead, but it will be slow. Her death will come because The Flash cares for her. Turtle always takes things that value most to people because his wife took him for granted and wanted to leave. He shows Patty his wife is now dead and preserved in a box. He has another box ready just for Patty.
At S.T.A.R. Labs Harrison figures out Turtle keeps these things he steals as trophies. Cisco can’t find him but then figures out Turtle’s ex-wife was an archivist at the Naydel Library before it shut down. That’s definitely big enough to hold all of the stuff he stole, and Barry takes off without a real plan. The gang tells him he has to grab Patty in between Turtle’s pulses. He’ll have two-tenths of a second to make his move. He confronts Turtle while he’s slow, and Turtle knocks him to the ground. The Flash races away only to return going full Flash speed. He’s able to move through Turtle’s pulses and eventually smashes Turtle into a wall, knocking him out and saving Patty. She still doesn’t know who he is, but she hugs The Flash and thanks him.
Turtle is locked up at S.T.A.R. Labs and The Flash tells him now he’s their most prized possession. Caitlin follows Jay out and tells him she knows he’s sick. She took his DNA off the champagne glass. She wants to know why he let her get close to him knowing she’d lose him just like she lost her husband. Jay reveals the only way to save him is to get his speed back, and the only way to do that is to stop Zoom.
Wally shows up at Joe’s using the excuse he left his sweater there. Wally’s going back to Keystone, telling Joe he’s not going to apologize for his actions. Joe says it’s he who should apologize for pushing this father/son thing. They agree to slow it down, and Wally agrees to stay for dinner.
At the Central City Police Station, Barry wants to talk to Patty and she says it’s not a good time. He doesn’t care and begins to explain that he hasn’t been honest. She cuts him off and says she’s leaving Central City because she’s going away to college to follow her dream. So, it’s time to move on from the job and from Barry. Barry’s devastated.
In a voice-over, Harrison says he’s coming for his daughter soon. He recalls how he lost her once when she was little, and will do anything now to get her back He goes to Turtle’s cage, shoves an instrument up his nose, killing him as he withdraws something.
And the final scene shows the arrival of another Reverse-Flash… It’s the real Eobard Thawne (Matt Letscher) and he has no idea where he is. This has to be the Earth 2 version of Thawne, but why has he shown up now? [Update: the producers have said it’s Thawne from an alternate timeline.]