The Flash star Grant Gustin reveals when Godspeed mystery will finally be addressed

Don't worry, The Flash hasn't forgotten about the Godspeed mystery.

In case you forgot, the CW superhero drama's season 6 premiere kicked off with Barry (Grant Gustin) chasing after Godspeed. When he eventually caught up to and umasked the faux speedster from the future, who was first introduced in the season 5 episode that shares his name, he discovered it was a version of Godspeed who was mute and simply emitted a high frequency. According to Cisco (Carlos Valdes), this was the fourth fake Godspeed they'd encountered. And that was the last time Godspeed was mentioned.

EW has learned, though, that The Flash will finally revisit this dangling thread in the season's 18th episode "Pay the Piper," (airing May 5) which, as the title suggests, also features the return of another rogue from the show's past.

"It's an episode where we're going to see some changes because of 'Crisis,' and Hartley Rathaway, [a.k.a.] Pied Piper, is going to be back," Gustin told EW earlier this week. "In that episode, Godspeed is back."

Given that the Godspeed clones all emit some weird noise, it makes sense for the sound-obsessed rogue to return in the same episode. The last time we saw Hartley (Andy Mientus) was in season 6's "God Friended Me,"which revealed that the bitter baddie-turned-ally went back to his villainous ways in the wake of "Crisis on Infinite Earths." In this new timeline, Hartley is no longer Team Flash's ally because, as Gustin puts it, "Barry kind of did Hartley dirty," and "Pay the Piper" will elucidate this fraught dynamic.

"Hartley really isn't a friend when he comes back, but Barry's going to need to find a way to reconnect with Hartley and try to fix what 'Crisis' changed and stop Godspeed, and try to save the city," says Gustin.

The Flash airs Tuesdays at 8 p.m. on The CW.

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