Crisis on Infinite Earths: Part Four

The episode is the fourth part of the five-part crossover, ​.

Synopsis
Stuck in the Vanishing Point, the Paragons search for a way to escape. The futility of the situation is compounded by The Flash's disappearance. However, hope appears in the form of Oliver, who reveals that he has become something else. Meanwhile, the origin stories for The Monitor and Anti-Monitor are revealed.

Production
Shooting for began on September 24, 2019.

Trivia

 * The part of the Crisis on Infinite Earths crossover was co-written by Marv Wolfman whose best known for co-writing the original Crisis on Infinite Earths in addition to co-creating the characters who made their debut in the novel including Harbinger, The Monitor, Pariah and the Anti-Monitor.