Last season on The Flash fans were introduced to Jesse Quick (Violett Beane) and Harrison Wells (Tom Cavanagh) from earth 2. At the end of season 2 we saw Jay Garrick from Earth-3, played by John Wesley Shipp, return them to their home on Earth-2 but according to a tweet from Violett Beane herself, that wasn’t the last that fans saw of them…
— Violett Beane (@violettbeane) September 30, 2016
It seems as though this will take place once the original timeline has been restored, fitting in with previous comments from the show-runners that the ‘Flashpoint’ arc will only last a few episodes, however, the synopsis mentions nothing about Cisco (Carlos Valdes) who is a millionaire in the altered timeline, so perhaps ‘Flashpoint’ could still be in full swing in this episode. The team had a great dynamic with ‘Harry’ and Jesse from earth 2 so it’s great to see those characters returning.
Fans have been wondering when Wally West and Jesse Quick would get their speedster powers given their characters in the comics also being speedsters. Last season they both got hit by the particle accelerator radiation so it was only a matter of time before they displayed their abilities. This happened in the original timeline so this could be further reinforcement that ‘Flashpoint’ could be over by episode 3. Even though Wally West is The Flash in the altered timeline, it is unclear whether or not he will have powers once the timeline is reverted back to normal.
Source: Violett Beane Twitter