After a brief hiatus, the CW’s “The Flash” returned Tuesday to show that the team hasn’t been relaxing since they’ve been away. As a result, they’re in desperate need of a night to blow off steam, which never goes according to plan for the hero of Central City. 

The episode opens with the team at S.T.A.R. Labs helping Barry Allen (Grant Gustin) get faster so that he’ll be ready the next time he gets to go toe-to-toe with Zoom, who was previously revealed to be a doppelganger of Jay Garrick (Teddy Sears). Sadly, the training isn’t going well. Barry is tasked with building up enough speed to clear a waterfall, but fails. When they return to S.T.A.R. Labs to figure out the problem, Cisco (Carlos Valdes) suggests that they’re been working too hard and that having fun will increase their overall productivity. 

Barry suggests they go out to the club. With the exception of Wells (Tom Cavanagh), everybody seems to be on board, including Wells’ newly rescued daughter, Jesse (Violett Beane). She begs her dad to let her go out, and he reluctantly agrees on one condition — she wear his big, goofy-looking tracker bracelet that beeps every few seconds.

Sure enough, it doesn’t take long before this little device poses a problem for her and her relaxing night out. As soon as it sabotages her flirty meeting with Wally West (Keiynan Lonsdale), she takes it into the bathroom to see if she can get it to stop beeping. When she does, she somehow taps into her father’s voice journal, right around the entry when he explains that he was willing to work with Zoom and kill people in order to keep her safe while she was the villain’s captive. 

While that’s happening, the dance floor is being interrupted by a familiar yellow blur, which rippled throughout the club stealing everyone’s wallets, purses and other valuables. Obviously, everyone thinks the culprit is The Flash, but Barry took off after the blur only to learn that it was faster than him.

The following day, with the population of Central City thinking that its hero had gone bad and the team trying to figure out a way to stop her, Jesse finds time to confront her father about the journal entries she saw. She’s unsurprisingly livid with him for crossing a very dark line in his efforts to save her. Meanwhile, with Barry bashing his head against the wall trying to figure out how to get fast enough to stop Zoom and this new speedster, Caitlin (Danielle Panabaker) finally tells him about the synthetic drug she made with Wells and Garrick called Velocity-9.

The drug is designed to help speedsters artificially increase their powers, which would explain how there’s suddenly another super-fast meta-human in the city. Barry is furious that he’s been working this hard while they’ve been sitting on an easy way for him to be faster, but Caitlin and Wells try to explain that the serum was killing Garrick and has clearly turned this other person crazy. That’s when Caitlin realizes that the only other person that could have had knowledge of V-9 is her old colleague at Mercury Labs, Eliza Harmon (Allison Paige). Apparently she reverse manufactured the drug after Caitlin gave her a few of its ingredients for a consultation. Now, she has been taking it to blow off steam, splitting her personality between Eliza and her drug-induced fantasy persona, Trajectory. 

While Caitlin and Joe (Jesse L. Martin) are off figuring all this out, Barry uses the opportunity to steal some V-9. He’s about to take it and train to stop Zoom when Wells catches him. Given that he’s been recently chewed out by his own daughter for compromising his morals, he’s in a unique position to convince the hero to stay off the drug and beat Zoom and Trajectory on his own terms. In the end, Barry makes the right call and smashes the vile on the ground. Before he can celebrate his personal victory for too long, S.T.A.R. Labs is attacked by a crazed Trajectory, desperate for another fix. She locks Barry away in a meta-human cell and steals Joe’s pistol. As soon as she turns it on Jesse, Wells agrees to give her more V-9, despite Caitlin’s protests that it’s killing Eliza Harmon.

The Flash "The Flash" Season 2, episode 16 saw the introduction of the first female speedster known as Trajectory (Allison Paige). Photo: The CW

Before she leaves, she takes one of the vials that Wells handed her and stabs it into Jesse’s neck to ensure it’s the real thing. Jesse starts to die, which means the V-9 is working. Trajectory leaves and Wells quickly submits to a blood transfusion and saves his daughter. However, when she wakes up she’s very upset to find out that her father was still making the same dark compromises for her that he was before. Eventually, it becomes too much, and she leaves him a voice recorded message explaining that she’s leaving Central City on a bus for Opal City in order to find herself. After spending months trying to find her and save her, she's chosen to walk out on him.

Meanwhile, Barry goes off in hot pursuit of the female speedster, who is purposely using her speed to create structural damage to a busy bridge. The Flash shows up just in time to save everyone fleeing from the rickety overpass, but it snaps in the middle nonetheless. This puts a giant gap between Trajectory and a really angry Flash. Invigorated by his pep talk with Wells, the scarlet speedster manages to reach his highest speed of the series and clear the gap. 

Caught off guard by the incredible feat of speed, Trajectory realizes she’ll need another dose of V-9 to take on The Flash. Before she injects it, the hero makes a heartfelt plea for her to let him help her kick the V-9 habit and save her own life. Sadly, she doesn’t listen and gives herself more of the drug than she can handle. She runs away from Barry, but when she does he notices something incredibly useful. 

Just before Harmon runs so fast that she literally disintegrates, her speed blur turns from yellow to blue, just like that of Zoom. Although saddened at the fact that he couldn’t save Harmon, Barry and the team go back to the lab and start to piece together what the blue streak may mean.

Barry hypothesizes that Zoom is going around stealing speed from people in alternate universes because it, coupled with V-9, must be the only thing keeping him alive. This would explain why he’s so much stronger and faster than The Flash all the time but also means that the likely candidate for Zoom is Garrick. That’s when Cisco decides to reveal that he’s been having his visions about the villain every time he gets close to Jay’s old helmet, which they’ve enshrined in the lab so as to honor their fallen friend. He holds it only to reveal to the team that his powers have allowed him to learn that Garrick is Zoom, or at least someone who looks an awful lot like him. 

The episode ends with Barry hearing that he’d been played this whole time by a man who he thought to be his friend. He runs back to the cliff where he knows he’ll be alone and lets out a primal scream of frustration. With almost all of the puzzle pieces in place, it seems like The Flash’s next encounter with Zoom is going to be a significantly different one. 

Fans who want to see what happens next should know that The Flash's next appearance won't be on the March 29 episode. Instead, he'll appear on the March 28 episode of CBS' "Supergirl," where he will crossover with Kara Danvers (Melissa Benoist).