“Cause and Effect” begins where “I Know Who You Are” stopped. The Flash confronts Savitar, who has been revealed as a future, evil, scarred Barry Allen. They talk about Savitar’s origin, which, to no great surprise, revolves around Iris’ death. Savitar is also a time remnant, so he has the additional strain of not quite being real. They end up in a big confrontation, and we learn that Savitar has a few really cool tricks that Flash doesn’t.
Back at STAR, Barry shares what he has learned with the team. Cisco, of course, starts riffing on old Star Trek episodes. They also figure out what the message from Barry of the future was about back during the Alien Crossover. Cisco maps out a somewhat confusing timeline of Savitar’s history as they now know it. They send HR to go check on Tracy’s progress on the speed trap, and Wally comes up with a great question.
As the team goes to do various things, Barry sits on the prop that looks like the comic’s Cosmic Treadmill. Iris comes to talk, and asks what the other Barry was like. They talk about what kind of person Barry is, and what may have made him Savitar. Barry also muses on the difference between a speedster and a god. Cisco comes in and says he has either the best or worst idea ever.
They’ve built a very fancy set up around a chair, and Barry jokes they’re going to give him a perm. Cisco’s brainstorm is that, if Savitar’s being a step ahead all the time is based on his memories being Barry’s, to stop Barry forming new memories. Unfortunately, as they point out, their bio-sciences expert was Caitlin, who’s currently giving them all the cold shoulder. The machine works… just a bit too well. Barry gets completely mind wiped. He doesn’t know anyone on the team, or his own name. Remember that best/worst idea thing? I know which way I’m voting.
The series of reactions to Barry not knowing anything was priceless, and a good acting job by Grant Gustin. From not knowing his team, or why he was at STAR Labs, to the reaction on hearing Wally was his brother, it was several great comedic takes. On a more serious note, Cisco and Joe try and figure out what happened and how to fix it. Cecile then calls and says she urgently needs to speak with Barry, just to make things more tense.
For an indication as to how well Tracy’s work is going, she’s yelling at her tools when HR comes in to check on her. Amid awkward scenes, they agree to name the device the Speed Force Bazooka (again, stepping on Cisco’s toes as naming guy). They also realize the depth of their mutual attraction and do their best to ignore it.
At the CCPD, Barry introduces himself as Bart, apparently the name his new self prefers. Cecile looks a bit surprised. That gets worse when they give her a rough explanation about what happened, leaving “Bart” totally confused. The emergency she needed Barry for was an emergency hearing for an arsonist going by Heat Monger. Great, now they’re being named after kids’ cartoons. Clearly, Barry is in no shape to testify. In the real world, that would be cause for a continuance. Here, it leads to low comedy and bad ideas.
After everyone else leaves, Barry sits on the couch worried that everyone is upset, even if he doesn’t quite get why. He and Iris talk for a bit, and we get a hint that Barry’s powers are at least buzzing away in the background. As all this goes on, Killer Frost finds out that Savitar has changed, too.
Iris tries to catch Barry up on what his life has been like before today. Bart is not impressed with Barry’s choices in high school. Iris notices that Bart is a lot lighter and happier than Barry. Then, they find out the hearing can’t be rescheduled and make the brilliant choice to have Bart go testify. He went by himself, which makes me wonder how the amnesiac Bart knew how to get there. They end up pulling a Cyrano de Bergerac style trick that works out like you’d expect on a bad sitcom. Heat Monger goes free.
Back at STAR, there are more problems. Apparently in some sort of time paradox, Savitar’s not having any memory means he never did most of the things he did, including giving Wally his speed, so Central City is fresh out of speedsters with Jesse being away on Earth 3. While this chaos goes on, Barry and Iris have gone back to their loft, and Barry asks something I’ve been wondering about for a while. They kiss, and his powers kick in, with no real hint of control whatever.
Barry is very excited about his powers, and they go back to STAR, where Killer Frost has turned up. She’s willing to help the team, since it will restore Savitar and she’s sure Savitar will eventually win. Reluctantly, the team agrees.
HR and Tracy continue being awkward until she just goes ahead and kisses him. He babbles in the aftermath, which is no surprise, as he’s usually babbling. Must be all the coffee. But this time, it’s useful, and gives her an idea to finish the bazooka.
Killer Frost agrees to help the others, but with a fair amount of mocking and scorn. Not at all subtly, Cisco tries to remind her of the good times she’d had in the building as Caitlin. He does get her to finish one of his stories for him, but aside from that, there’s not a lot of headway. Meanwhile, down in the Speed Lab, Barry is very excited about his powers and zipping around the track while Joe and Iris talk about the odd situation.
Things get more tense when the recently-freed Heat Monger strikes again. He was out what, a few whole hours? He lights a high-rise on fire, and Barry decides he has to go, even as inexperienced as he suddenly is. Finally, due to a combination of guilt about the people in danger and Iris talking him through some painful memories, Barry gets his memories back, and, as the effects ripple up the timestream, Savitar remembers and Wally gets his powers restored. The two heroic speedsters easily best Heat Monger, who the system will hopefully not spring on another technicality in a few more days. Killer Frost takes her leave with some ugly parting words, but we get a hint that Cisco was getting to her.
The episode ends oddly. After the expected mushy reunion between Barry and Iris, they get interrupted by HR. He and Tracy have a classic good news/bad news situation. Tracy finally got her stuff together and has designed the Speed Force bazooka. Unfortunately, it needs a power source beyond anything they’ve ever seen. We get a hint at what’s coming next episode, but it’s really, really weird and seems to come from nowhere.
What I liked: Grant Gustin played amnesia Barry wonderfully. There was a lot of comedy, especially in the first few minutes. There were some really sweet Iris/Barry moments in here as well. I’m hoping the elevator scene with Killer Frost was a good omen. The HR/Tracy scenes were nicely done, too. The reveal of Barry’s full name, just like it is in the comics, was a nice Easter Egg for obsessive comic book readers like me. Savitar is right as far as him having a cooler suit than Flash’s.
What I didn’t: Having Barry go to court with no memory was ridiculous. It just plain made no sense. I’m not sure I buy Kid Flash losing his powers the way he did. The ending made no sense at all, and the preview for next episode even less.
Mostly for mind-wipe Barry, I’ll give this a high 3.5 out of 5. We’re almost at the season finale, and I’m really, really hoping that’s the end of Savitar. Maybe next season we could have a non-speedster as a bad guy? Flash does have other enemies.