Iris tells Barry she just had a date, but it reminds her of Eddie. And dating feels wrong.
Talking with Wally at dinner about reading all of his heroes' books, Barry decides to go back in time to learn from Harrison Wells. Harry is disgusted. He warns Barry that Thawne will know it's him and that will affect the timeline and when he comes back, that means he'll notice things are different and he'll be the only one who knows that.
The scientists decide he'll go back to when Hartley Rathaway was around, because that's when they first learned Wells/Thawne knew the particle accelerator was going to explode.
Cisco and Caitlin start coaching him on how to make it all work, and as it's happening and Barry says, "what could go wrong," you just know something is going to go wrong.
Barry arrives too early. It's not a good start.
Barry then makes the real Flash go away, by way of tranq dart. Back at the Lab, he remembers Hartley's ear implants and the bomb. He gets that taken care of and then screws up by showing his scientific hand with Wells/Thawne. WT almost stands up to catch the lie. He doesn't.
There is a wraith attacking in the station. It was in the Speed Force as Barry came through. Barry then says he thinks the CCPD has whatever is plaguing them handled. Ummm. no. Run Barry. I miss WT saying that.
Finally. Something good about this episode. Hartley was being Rick Rolled.
Barry gets Eddie to say something to Iris in a birthday video as if it's the last thing he would ever say to her.
The two Barrys are in the same room. It's ridiculous in a way only The Flash can do it.
WT gives Barry the tachyon stuff on a USB drive. Or something. He's sending Barry into the Speed Force to get rid of the Wraith.
Our Barry needed help to get going and other Barry pulled a Supergirl to get him going. The Time Wraith went through the Speed Force though, and was sucking the life out of him. Thankfully, Hartley saved him.
Um...yeah, because Hartley is just a little something that changed by way of messing with the timeline.