Green Arrow and The Flash help Kendra Saunders and Cartel Hall from the hands of the villain Vandal Savage while the team develops a weapon against Savage in "Arrow" season 4 episode 8.

"Arrow" season 4 episode 8 is entitled "Legends of Yesterday," the follow-up to "The Flash" season 2 episode 8, which is entitled "Legends of Today." According to Spoilers Guide, the episode sees Oliver Queen and Barry Allen take Saunders/Hawkgirl and Hall to a far place to hide them from Savage while they craft a plan to defeat him.

The episode also sees Malcolm set a meeting with Green Arrow, The Flash, and Savage, which does not become successful as planned. Also, Felicity Smoak, Thea Queen, John Diggle, and Laurel Lance work hand in hand with The Flash's team to create a weapon strong enough to take down Savage.

The Flash himself, Grant Gustin, also revealed some details in the second part of the major "Arrow" and "The Flash" crossover event. In his interview with Entertainment Weekly, Gustin said that the crossover event was huge and fans would see a lot of characters interacting that they did not normally get to see interacting.

For Gustin, they poured their full effort to film the two episodes, which are set to pave the way for the upcoming television series "Legends of Tomorrow."

Meanwhile, in "The Flash" season 2 episode 8, "Legends of Today," Savage reached central City and attacked Saunders and Cisco, leading them to ask help from Allen. Since he knew how dangerous Savage was, Allen brought Saunders to Star City and asked Oliver and the team to hide her until he could find a way to defeat Savage.

Hawkman entered the scene and flew off with Saunders, making things worse. Harrison also made a serum that would improve Allen's speed and asked Jay Garrick to try it out.

"Arrow" season 4 episode 8, "Legends of Yesterday," airs on Dec. 2 while "Legends of Tomorrow" debuts on Jan. 21, 2016.