The title of the ep is 'Rupture', but make NO mistake - this one is all about Zoom and his mission to destroy Earth 1 and Barry Allen.
Our story begins with the Star Labs Scooby gang making with the science, using a Holo-Flash to fight crime since Barry is so turtle-like now. Wells is bitching (as usual) that Barry is nothing without his speed, and he intends to use another particle accelerator explosion to get it back. For now the gang is united in the belief that the risk outweighs the reward.
Barry is pining for better times, so he visits his birth father Henry up in the wilderness somewhere. He proceeds to tell Dad his tale of woe, and wonders out loud whether he should take the risk to get his speed back. Henry responds as any Dad would, telling Barry that the speed doesn't make the man.
Back at the lab, Cisco 'vibes' that his estranged bro Dante is in danger and jets off to find out what's what. Soon after, Barry comes back to the lab with Henry in tow. Dad is going to stay with Barry to support him in this difficult time.
Joe is having a heart to heart with Wally at the po po station when guess who shows up?
Zoom and Caitlin! Zoom threatens to kill all the cops unless they evacuate the station, but relents when Cait begs him to stop. The cops bug out to the coffee shop C.C. Jitters next door to plot their next move.
Joe goes to the lab to find out from Wells what Zoom's endgame is. Wells recounts how Zoom slaughtered all the cops on Earth 2 and recruited all the metas so he could conquer the planet. Sounds like the he's gonna run the same game on Earth 1, huh?
Back at the police station, Jay Garrick (serial killer Hunter Zolman) rebuffs Cait's pleas to be merciful, saying that the only one he will leave alive is her. He tries to bring out the dark side in Cait, just like her doppelganger Killer Frost on Earth 2.
Cisco finds Dante and they go to a bar to reconnect. Once there, Cisco sees a news report about Zoom's takeover of the po po station and he bolts out to the street, with Dante in pursuit. Next thing you know, a masked dude with an electrified scythe attacks them! The dude is named Rupture, and he's a meta who's in league with Zoom. But here's the surprise - He knows that Cisco is Vibe! And how does he know this? Well, he takes off his mask and he looks exactly like ... Dante! So he is the doppelganger of Dante on Earth 2, and he thinks that Vibe (Cisco) killed the HIS bro, the Cisco doppelganger on Earth 2! OK, now I have a headache!
Anyhoo, Cisco and Dante escape and go back to the lab to tell everyone about the new threat.
Cait overhears Zoom and Rupture planning an offensive on the police at Jitters, and somehow finds a phone (even though she's cuffed) and texts the gang, warning them of the impending attack. Now the debate reignites about bringing back Barry's powers.
This brings us to the most heartwarming part of the ep - Iris gets Barry alone and FINALLY tells him about her romantic feelings for him. She loves him for HIM - no superpowers needed. Barry seems really stoked about this turn, and it shows.
Rupture infiltrates Jitters, looking for some cops to kill. What he finds instead is Holo-Flash, and a fight ensues. Barry does his best motion-capture performance ever, and the police taser Rupture, incapacitating him.
Zoom sees the media reports of the Rupture capture and, well, Zooms over to Jitters to kick some ass. And that he most assuredly does, killing everyone but Joe and Rupture. He then attacks Rupture and offs him. Zoom picks up the video camera from a slain news crew and tells the city that The Flash they see is a hologram - a fake. He then warns Joe that it's only his affection for Cait that is keeping Joe alive.
With the revelation in the media that The Flash is really a fake, the debate begins again about restoring Barry's speed. Wells piles on with the info that there are many more unaccounted for metas out there than the gang even realizes.
Barry decides that The Flash is 'the best version of me' and agrees to go forward with the plan. Part of the plan involves recreating the lightning that struck Barry during the explosion. Enter Cisco - he has a gizmo that can do just that. He just needs to go to the roof to make it happen. Once on the roof, Cisco does his best Harry Potter and makes lightning!
One sidebar which now becomes very important to the story - Wally and Jesse were sequestered in a locked room to shield them from Zoom. Wally sooo wants to help people (since he was saved by The Flash) that he talks Jesse into escaping from the room. She cracks the lock and they escape down the halls of the lab. This coincides with the particle accelerator going off, and they get washed over with an energy wave. Will this give them meta human superpowers? In the comics it does, with them becoming Kid Flash and Jesse Quick. My guess is yes.
Back in the main lab now, where Barry is getting seriously zapped. Almost instantly it seems to go sideways, and Barry starts to disintegrate!
And disintegrate he does - winking out into nothing. Everyone is obviously horrified, with Iris collapsing into Joe's arms, weeping uncontrollably.
Zoom makes the scene for a victory lap and taunts Wells, telling him that he killed Barry instead of helping him. The ep ends, zooming in on the last, smoking remnant of Barry's suit - the bolt logo on the chest.
One more thing:
In an earlier talk with Henry, Barry divulges that Zoom is Jay Garrick. Henry tells Barry that Garrick was his mother's maiden name. So could it be that the 'man in the iron mask' on Earth 2 is Henry? Or a younger version of Henry? Or a relative of Henry? Add to this the actor who plays Henry now played The Flash in the 1990 series version and it becomes very interesting indeed!