Zoom brought The Flash to his knees all on his own, but to take down Central City, the demonic speedster will need an army.

Hunter Zolomon (Teddy Sears) is no stranger to scooping up rogues and sicking them on the unsuspecting denizens of Earth-1. When season 2's penultimate episode rolls around, however, Zoom will up the ante. Titled "Invincible," the hour could turn Central City upside down.

"After Zoom unleashes an army of Earth-2 meta-humans on Central City, Barry (Grant Gustin) is shaken when he sees their leader is the Black Canary's Earth-2 doppelganger, the Black Siren (guest star Katie Cassidy)," The CW teased. "Meanwhile, Wally (Keiynan Lonsdale) takes to the streets to help The Flash stop the meta-humans, which worries Joe (Jesse L. Martin)."

Barry won't be the only one thrown for a loop by Laurel Lance's doppelganger. The Arrow staple bit the dust few weeks back, and her sudden return will hit close to home for Cisco.

"Cisco reacts in a pretty unexpected way," Valdes told Entertainment Weekly. "There's a little bit of a morbid shock, because the characters have an awareness to the fact that Laurel Lance is dead. That death had some effect on these characters in this world. So to see Black Siren, more than anything, is a shock to the senses."

Poor Vibe. He certainly won't fanboy over this particular meta, let alone take a selfie with her.

Meanwhile, Barry's dad will continue to fret over his son's safety. Henry Allan (John Wesley Shipp) will voice speak out against Harry's plan to restore the Flash's speed in next week's "Rupture," and Iris (Candice Patton) will join him in worry during episode 22.

Find out more when The Flash airs Tuesdays at 8 p.m. ET on The CW. Click the video below to see a preview for the series' next episode.