The only word I can think of to describe how The Flash has felt the last few weeks is "stuck." It's very literal, too. In the real world, our noble but sometimes dumb hero Barry has been watching his speed drain away. Meanwhile, Iris has been stuck in the mirror universe. Only Ralph Dibny and Sue Dearbon have really had any forward momentum. That changes this week as Barry figures his stuff out and Eva makes a big move. It makes for one of the better episodes of the season, even if a lot of the motivation involves hand-wavey sci-fi science. Spoilers follow for The Flash Season 6, Episode 17, "Liberation."

"Liberation"

An experiment to create an artificial Speed Force wrong. Cecile gets a weird vibe from Iris. She finds Barry in her house, surrounded by boxes. Behind him is one of those glass markerboards that sci-fi shows love so much, and a corkboard that's only missing red string. Barry has finally put the pieces together and has figured out that Iris isn't Iris. Aside from her badass attitude, her new language skills, and her aggressive behavior, even Barry can tell how strange and yet how silly it is that Iris is suddenly a competent cook.

Cecile is a little freaked out, but she takes Barry seriously. They find the refracted photo of Mirror Iris in Kamilla's cloud account, confirming Barry's suspicions.

My superpower is narrative propulsion

As I mentioned above, there's a lot of hand-wavey sci-fi science in this episode. I mean, there is in The Flash in general. The show plays fast and loose with what the Speed Force can do the same way the comics have through the years. But Cecile's power to sense emotion seems to work with the same laws of physics that plot armor does in shows like Game of Thrones. It works and doesn't work when the plot demands it. Why hasn't Cecile noticed that Iris is off? Why hasn't she gone to Joe or Barry about it?

Apparently this is enough evidence for her, though. With the help of Cecile and Nash, Barry corners Iris in Star Labs, ready to scan her with a refractor device. For some reason, though, it fails miserably, and it's Barry that ends up looking crazy. They lock him up in the pipeline for a while, but once again, Cecile knows Barry and knows that he's him and believes what he's saying. She lets him out.

Cheap Trick

Here's the second hand-wavey moment. We find out later that the scanner didn't work because Barry just happened to leave it on a mirror, which allowed Eva to swap it out with a mirrored refractor. How did she create the mirrored refractor? She seems to have to build everything else. The show suggests that Mirror Iris and Eva knew that Barry would have a refractor and that he would somehow leave it on a small mirror so that Eva could swap it out.

There's no foreshadowing here to plan any of this out; it feels like cheap magic when the trick is explained. As an aside, I'm rewatching the NBC sitcom Community alongside all my Arrowverse shows. There's an episode where Annie, the overachiever academic character, loses her pen. It turns into a whole thing and everyone ends up dumping out their backpacks and taking off their clothing. In the final moments of the show, we see that a monkey that had escaped earlier in the show stole the pen. If you rewind back to the beginning of the episode, you can see in the background that the monkey reaches up and snatches the pen on camera. It's subtle, but it's there.

Flash doesn't even do that. There's so much happenstance in this plan of Eva's that it gets in the way of me suspending disbelief. You ask Mom 'why' and she says 'because I said so," and that's all the more you get. That's fine when you're five years old and trying to put a fork into the electrical outlet, but it's more unsatisfying when a show does it.

Bloodwork Returns (for a second)

While Barry is locked up, Mirror Iris meets with her fellow reflections, Kamilla and Singh. They break into ARGUS where our very icky friend Bloodwork is being held in a bio-degradation field that suppresses his powers. For once, I actually understand a character being held inside a small area with no bathroom. Bloodwork isn't human. He doesn't need any of that stuff.

We learn that Eva needs some of Bloodwork's inky ichor to execute her plan. The show never tells us why his blood matters, though, and it seems like an excuse to loop back to the old villain. I enjoy Sendhil Ramamurthy as Bloodwork, so I'm not going to complain, but it feels forced. What also feels forced is when Mirror Kamilla walks into the forcefield to deactivate it. Again, we're never told why. Just that Eva has a theory it'll work. Interestingly, Bloodwork decides to stay in his cell, saying he's playing a long game. Alright, then.

Mortal Combat

Once released, Barry finds Iris in their condo, surrounded by mirrors, and this is where stuff starts to get enjoyable. Barry and Mirror Iris duke it. Barry doesn't have his speed, and Mirror Iris is surrounded by mirrors. Without any reason to hold back, Iris douses one of the mirrors with Bloodwork's goop and shapeshifts her arms into blades, T-1000 style; Barry and Mirror Iris fight it out.

This is one of the better fights of the season and maybe even the show. It has the high stakes and emotional charge we've been missing. Mirror Iris has been, with each passing day, developing a will of her own, and she knows that she's going to have to die for Eva to live. Barry knows this Iris isn't real and that the real Iris is somewhere. They're both fighting for their lives. There's great fight choreography and visual effects here, and they help tie together this emotional fight.

Barry's losing badly, but something happens.

Iris Fights Back

On the other side of the mirror, Iris notices Eva's agitation. She's pushing against Eva this week. Earlier in the episode, she found a button on the side of the big mirror that revealed a secret room.

Let's pause again. I have a gripe about the mirror world. All the writers have told us about the mirror world is that it's the mirror world. We don't know anything else about it. I don't need to watch Iris eating mirror crackers or going to the mirror bathroom, but I want to know more about what the last few weeks have been like. I want to know anything about what the past few weeks of life have been like. Instead, the show treats them like the five minutes we've been given.

I've been in isolation for a month now. My hair is longer than I'd like. My beard is scraggly. Iris has been in isolation for about as long, but she looks like she just left the makeup trailer. Does she have to eat? Does she sweat? She should look more physically and emotionally distressed than she does. How far does the mirror world go? We saw Iris in a storeroom a few weeks back. Is there a whole city? How did Iris not notice a button on the side of her room's central feature?

Anyway, the secret room has mirror monitors that... reveal all of Eva's secrets to Iris for some reason. Iris faints. She wakes up tied to a chair. Iris notices that Eva is becoming agitated and distracted; she's dividing her focus between executing her plan and executing Barry. Iris taunts her and psyches her out, breaking her concentration. She starts that compulsive scratching we've seen her do, and it bleeds over into Mirror Iris.

Reflecting on the Episode

Barry is able to break through and talk Mirror Iris in trying to embrace her free will, which saves him and kills her as she shatters into a million mirror shards. Eva comes out of the mirror and kicks Barry's ass before telling him that he's no threat to her. Barry falls unconscious. When he wakes up, he looks into his mirror and talks to Iris, though he can only see his reflection. The show does one of those hammy things usually reserved for musicals, where the two characters on either side of the mirror say similar things about each other to each other, even though the other can't hear it. It's sweet.

Oh, and we can't forget about the C-plot this week, which has Cisco and Ralph visiting the injured Caitlin, still recovering from her wounds from Dr. Light. They find her in an ice coma and have to wake her up. It feels extraneous; it's the very definition of 'give them something to do.'

Even with all the hand-wavey science stuff, I still enjoyed this episode because it delivered emotionally. It offered a great climax to a lot of build-up and some genuine catharsis. And it made a great fight for a speed-less Barry, which is a tough order. I'm done with The No Flash and ready for them to bring back my favorite superhero, but in the meantime, I'm glad they squeezed a good episode out of all this.