The CW has released the official synopsis for "Crisis on Infinite Earths Part Two," the December 9 episode of Batwoman that will introduce the multiverse to Gotham's caped heroine. In this episode, Kate (Ruby Rose) and Supergirl (Melissa Benoist) go in search of Bruce Wayne -- and they find him, but not exactly the one Kate might be expecting. Encountering Kevin Conroy's older Bruce might be a bit of a trip, but it will be even more interesting for Clark Kent (Tyler Hoechlin) and Lois Lane (Bitsie Tulloch) to meet up with another Superman. And somebody who will probably be even more annoyed by the multiple Supermen? Lex Luthor (Jon Cryer).

No clue yet on what role Luthor will play, and it's hard to know what side he will even be on. A TV spot for the event appeared to show him shoulder to shoulder with Supergirl, staring down an unseen foe. For now, you can check out the official synopsis below.

CAN THE REAL CLARK KENT PLEASE STAND UP? PART TWO OF CRISIS ON INFINITE EARTHS CONTINUES WITH SPECIAL GUEST STARS TOM WELLING, ERICA DURANCE AND KEVIN CONROY – The group uses Ray’s (guest star Brandon Routh) invention to track new recruits to help save the universe. The Monitor (guest star LaMonica Garrett) sends Iris (guest star Candice Patton), Clark (guest star Tyler Hoechlin) and Lois (guest star Elizabeth Tulloch) in search of a mysterious Kryptonian, while Kate (Ruby Rose) and Kara (guest star Melissa Benoist) head out to find Bruce Wayne (guest star Kevin Conroy). In addition, Mia (guest star Katherine McNamara) challenges Sara (guest star Caity Lotz), Rory (guest star Dominic Purcell) discovers a hidden talent, and Lex Luthor (guest star Jon Cryer) returns. Laura Belsey directed the episode written by Don Whitehead and Holly Henderson.

"Crisis on Infinite Earths" has loomed over the Arrowverse for years. The series premiere of The Flash featured an allusion to the hero disappearing amid red skies in the year 2024. During the original comics event, red skies were a sign of doom to come to a world during the Crisis. At the end of last season, a couple of things happened: The Monitor (LaMonica Garrett), who had appeared in "Elseworlds," reappeared and revealed that Oliver Queen was destined to die in the Crisis...and the future newspaper at STAR Labs rolled back the expected date of the Crisis from 2024 to 2019.

In the comics, Crisis on Infinite Earths centered on a battle between the combined superheroes (and even some villains) of the DC multiverse and an immortal, cosmic threat known as the Anti-Monitor. Like The Monitor, the Anti-Monitor will be played by LaMonica Garrett in the Arrowverse. As the Anti-Monitor destroys realities, he replaces their positive matter energy with antimatter, growing his own power and sphere of influence. He was eventually stopped by the sacrifices of several heroes, including The Flash and Supergirl, as well as the merging of multiple universes to save reality by becoming a single, unified timeline. Fans have long wondered whether the events of "Crisis on Infinite Earths" might bring Supergirl and even Black Lightning to Earth-1, where the rest of the series take place. The crossover will also feature guest appearances by Tom Welling as Clark Kent, Erica Durance as Lois Lane, John Wesley Shipp as the Flash of Earth-90, Johnathon Schaech as Jonah Hex, Kevin Conroy as Bruce Wayne, and Ashley Scott as The Huntress.

“Crisis on Infinite Earths” kicks off on Sunday, December 8 on Supergirl, runs through a Monday episode of Batwoman and that Tuesday’s episode of The Flash. That will be the midseason cliffhanger, as the shows go on hiatus for the holidays and return on January 14 to finish out the event with the midseason premiere of Arrow and a "special episode" of DC's Legends of Tomorrow, which launches as a midseason series this year and so will not have an episode on the air before the Crisis.