Crisis on Earth-X, Part 1

"Crisis on Earth-X, Part 1" is the upcoming eighth episode of the third season of Supergirl, and the fiftieth episode overall. The episode is the first of a four-part crossover with the eighth episode of the sixth season of Arrow, eighth episode of the fourth season of The Flash and eighth episode of the third season of DC's Legends of Tomorrow. It will air on November 27, 2017.