This week’s episode was about something The Flash is familiar about: time travel. Barry deduces that the only way he can get fast enough to defeat Zoom is to go back in time and have Dr. Wells/Eobard Thawne teach him. The team doesn’t agree with this idea at first, but seeing they have no other option eventually go along with it. Caitlyn gives him a serum to knock his past self out with. Barry travels back in time and while he is running something chases him. When he arrives back in the past he knocks his past self out and recaptures Hartley.
When he goes back to Star Labs, Eobard figures out he is from the future and attempts to kill him. Barry is able to convince him that his plan works, but Barry has to become faster. The creature following Barry was revealed to be a Time Wraith and Cisco and Caitlin had to accept help from Hartley in order to defeat it. Eobard gives Barry what he needs to get faster, and Barry tells Cisco and Caitlin to come up with a plan to defeat the Wraith permanently. When Barry returns to his own time,Cisco and Caitlin’s plan didn’t work, but present time Hartley arrives to help the team defeat the Wraith.