Arrow Heads to Lian Yu in Final Midseason Finale "Purgatory"

The CW has released the official synopsis for "Purgatory," the eight and last-ever midseason finale for Arrow. The episode, which will air on December 3, will be the last Arrowverse episode to air on The CW before "Crisis on Infinite Earths" begins the following Sunday. In the episode, Oliver heads to Lian Yu. It is not yet clear who he will run into, but it sounds like both Oliver and the rest of Team Arrow are up for a pretty big fight before they settle into the events of "Crisis" and the culmination of their travels working for (or is it against?) The Monitor.

The weirdest part of it all? According to this, Oliver "receives help from an old friend." And the episode includes a guest appearance by Byron Mann -- Yao Fei, the man who gave him his first hood and quiver. That's quite a full circle to come just before the end of the series.

You can check the official synopsis out below.

BYRON MANN GUEST STARS – Oliver's (Stephen Amell) mission takes him to Lian Yu where he tries to ignore the repercussions of the looming Crisis until he receives help from an old friend. Meanwhile, a united Team Arrow faces a recognizable villain. James Bamford directed the episode written by Rebecca Bellotto & Rebecca Rosenberg.

Arrow airs on Tuesday nights at 9 p.m. ET/PT, following episodes of The Flash on The CW.

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.