Barry Allen (Grant Gustin) asks Harrison Wells, a.k.a. Eobard Thawne (Tom Cavanagh) why he killed his mother in the first clip from the season finale of The Flash, "Fast Enough", airing Tuesday, May 19 at 8 PM ET on The CW. We previously saw part of this scene in The Flash Season 1 finale trailer that debuted last week, but this sneak peek gives us more details about Eobard Thawne, who says he hates Barry because they are enemies in the future. Eobard also reveals that he is first "born" 136 years from now, but he won't say exactly why they are enemies in the future, because "it doesn't matter."

Eobard also says that neither him nor Barry were strong enough to defeat one another, until Eobard learned The Flash's secret, that he is named Barry Allen. Unfortunately, we don't get a glimpse of the final fight between Eobard and Barry, but we know that Barry will get some assistance in this battle from Dr. Martin Stein (guest star Victor Garber) and Ronnie Raymond (guest star Robbie Amell), who return to help the S.T.A.R. Labs team. The trailer released last week showed an adult Barry reuniting with his mother, after supposedly saving her from Reverse Flash's attack that killed her several years ago.

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The Flash has already been renewed for a second season, which will debut next fall on The CW, but we'll have to wait until tomorrow night's Season 1 finale to see how this new season will be set up after the final showdown between Barry and Reverse Flash. What do you think will happen in The Flash Season 1 finale tomorrow night? Check out the clip below, and tell us your theories on the finale below.