Part one of the arc will have Barry, Oliver, and Ronnie/Stein facing off against Reverse Flash at the beginning of the episode and actually doing alright. During the fight, or beforehand, Barry needs to find out about Eoard stealing the real Wells's body. The fight ends with Barry going back in time to save his mother and triggering the Flashpoint timeline. When he gets to the changed timeline, his powers are completely drained just like Eobard's powers were in the Tricksters episode. He tries to take a cab to Star Labs, but no one will take him to Central City. So he walks. As he is leaving the suburbs, he is attacked by [insert villain from one of the first few episodes here]. Barry tries to run away, but then Cisco jumps in to save the day as Vibe. It's a pretty easy win for Cisco, because as we learn shortly afterwards, he has defeated said villain before on more than one occasion. Barry explains to Cisco that they're good friends and that they fight crime together, except usually Barry has metahuman super speed, and Cisco doesn't have vibration tech. At first Cisco doesn't believe him, but Barry goes on to tell Cisco everything he knows about him and everything about the original, and Cisco's eyes grow wider and wider in disbelief. Cisco tells Barry about the differences with this timeline. For example the year isn't 2015; it's 2022, and instead of "team Flash" it's "the Resistance". They go back to Star Labs. There, all the members are introduced. We have the real Dr. Wells (still in a wheelchair), Leonard Snart as Citizen Cold, Sara Lance as the Canary (with powers), Wally West as the Flash of this universe, and Linda Park (in place of Lois Lane). After Barry meets them all and learns how them became a team, he asks if they know Ronnie Raymond or Martin Stein. Wells says that they both died when the particle accelerator exploded, and Caitlin Snow, a former Start Labs employee, became a metahuman who goes by the name Killer Frost. She blamed Start Labs for the death of Ronnie and has since formed a team of Rogues that has burdened Central City and Star Labs. Barry says that in his universe they were thought to be dead, but actually they were both turned into an amalgam methuman with fire powers, and that they need him to stop Eobard Thawne. They do some digging in some "secure" government files and find that shortly after the explosion, Ronnie Raymond was captured by ARGUS and kept imprisoned for scientific research. They agree that they need to free Ronnie. They head to the facility where he is being held, but since Cisco, Sara, and Snart don't have super speed, the gang takes a van. On the way there they are met by Caitlin and the Rogues.