Legends of Yesterday

"Run, Barry, run."

- Oliver Queen encouraging Barry Allen to go back in time in order to save themselves from Vandal Savage.

"Legends of Yesterday" is the eighth episode of the fourth season of Arrow and the seventy-seventh episode overall. The episode is the second of a two-part crossover with the eighth episode of the second season of The Flash. It serves to set up the upcoming series, DC's Legends of Tomorrow.

Synopsis
Oliver and Barry Allen take Kendra Saunders and Carter Hall to a remote location to keep them hidden from Vandal Savage while they figure out how to defeat him. Malcolm arranges a meeting between Vandal, Green Arrow and The Flash that doesn’t go as planned. Meanwhile, Felicity, Thea, Diggle and Laurel work with Team Flash to come up with a weapon powerful enough to destroy Vandal Savage.

Production
Preparation ran from September 22 until September 30, 2015. Shooting ran from October 1 until October 15, 2015.

Trivia

 * Thea says, "A bunch of superheroes in a farm house. Feel like I've seen that in a movie before." This is a reference to Avengers: Age of Ultron, in which the Avengers hide out on Hawkeye's farm.