(Disclaimer: There is not many pictures circulating the internet from this topic, so don't expect to have a visual sense of what I am saying.) You may have seen the new Flashback trailer for the upcoming episode of The Flash. It hints at quite a few things, mainly discussing a time wraith and time jump throughout the trailer. I am going to try and analyze them and see what I can find and conclude.
Let's start with the first thing we see, Dr. Wells hurls a left hook into Barry's temple, then cutting to a scene with Barry chained to a metal object, but not before a peculiar seen of Barry standing infront of the Particle Accelerator door in an ominous stance. We can't say much about that in particular since there is almost no context, but I am going to say Wells is unsure of Barry's intentions about something, not sure what, just Wells may be afraid of what Barry might do given the right opportunity. With Wells questioning "Who are you?" and not seeming to want to be lied to.
Then Barry is walking around a corner, to a crime scene of what looks like 'The Flash' stopping Hartley Rathaway surrounded by cops. This scene really matters I think, it means Barry has for sure time jumped, but differently in the sense it didn't erase his past self from ever doing that day, both Flashes are still there, stopping crime. This would help with Dr. Wells, but it is a different Wells, making it un-needed. The time they stopped Hartley was Season 1, Episode 11. Whilst, the latest episode was Season 2, Episode 16. Yet, it still may help us with Dr. Wells, just not the Wells from Season 2, the Wells from Season 1. Dr. Wells of Season 1 was also a speedster and wanted to be the only speedster around, so he had to kill 'the Flash'. He kept that a secret of course since he worked with 'The Flash' but then all of a sudden there is two of them, he would for sure have some questions, moving on!
Dr. Wells realizes "No, you're from the future" with Barry saying "I remember this," looking at Hartley. The big problem here is Dr. Wells knows Barry is from the future, meaning that Wells' knows he fails at killing Barry. This could potentially cause major time disruptions since he knows he fails, Wells with probably change his plan and may just kill Barry while his back is turned. So that is a major problem.
The Time Wraith is mentioned as an enemy in this episode, Dr. Wells mentions it only comes after people who travel back in time. This brings up a lot of questions though, why did The Time Wraith not come after Barry when he time jumped before? Why is there no DC history on this thing before this episode? Is it somehow related to Zoom and Earth Two? All questions hopefully to be answered in Episode 17. It then flashes (flashes-flash, heh) a bunch of images on the screen, not much of a story to be told through that. Then Dr. Wells finishes his explanation of the Time Wraith, with it only comes after people who travel through time and don't know what they are doing. Meaning Barry somehow managed to mess something up he probably shouldn't have. This might be the enemy to fill these couple episodes before Zoom gets back from Fiji and decides to be a supervillain again.
The Time Wraith pops out of a wall and then it cuts away, with the Flash from this timeline pinning our Flash to a wall. It doesn't stay on screen long enough to make it out if Flash from Season 1 wants answers, or wants to fight. Either way it'll be really freaking cool. It cuts back to the Time Wraith pinning Barry to the ground and attacking him, with Cisco and Caitlyn watching helplessly. Wells then jokingly says to what we think is the Flash "Scary, aren't they?" Yes, yes they are.
The Wraith is then floating through the accelerator hallway, while the words FEAR THE WRAITH pop onto the screen one at a time until the Wraith is right next to the Accelerator door, when it cuts to Cisco, Caitlyn and Hartley standing in the meta-human containment thing. The trailer ends with what we are all thinking, Hartley saying "Ho-ly, Harry Potter." That gave me a little smile, you know, even though it's Hartley.