Grant Gustin Teases Heartbreaking Flash Finale

05/14/2015 10:22 am EDT

While next week's season finale of the Flash looks to be pulse-pounding, series star Grant Gustin is promising that will also breaks viewers' hearts. 

Gustin, who plays Barry Allen/The Flash, teased fans (via Twitter) with the promise that "Next week's finale of The Flash is truly heartbreaking."

Indeed, it certainly looks like next week's episode will include some sentimental moments. As preview trailers have  shown, Barry succeeds in traveling to the past. In doing so, he will reunite with his long-dead mother, whom the Reverse Flash killed (also via time travel) when Barry was just a child. Their reunion looks to be a tearful one, hence Gustin's promise of a broken heart.

Then again, maybe Gustin is teasing a tragic setback in Barry and Iris' troubled romance, the death of an important cast member, or something else entirely. It's tough to say given the vagueness of Gustin's message. But no matter how events might pan out, be sure to have a box of tissues nearby. 

The Flash's season finale, "Fast Enough," airs May 20 at 8:00p.m. on The CW. 

Disclosure: ComicBook is owned by CBS Interactive, a division of Paramount. Sign up for Paramount+ by clicking here.