Arrow/The Flash
A still from the Arrow/The Flash crossover episodeThe CW

This season's Arrow and The Flash crossover episodes are extra special for fans as well as the makers as it sets the stage for CW's eagerly-awaited spinoff series, Legends Of Tomorrow. The two-part crossover -- kicking off on The Flash season 2 on 1 December 2015 -- will feature a host of superheroes so we can expect tons of action and entertainment.

"We shot a scene that had, like, nine superheroes in it," Amell revealed during a recent roundtable. "Nine people with either powers or super-suits. It was an amazing thing to look out over the scene and see the world that has been built over the course of three-plus years." (via ComicBook).

The CW has released the official synopses for part 1 and part 2 of the crossover episodes. Check it out below:

The Flash/Arrow Crossover Part 1 titled Legends Of Today - on The Flash season 2

"In its second major crossover event with 'Arrow', Vandal Savage (guest star Casper Crump) arrives in Central City and sets his sights on Kendra Saunders (guest star Ciara Renée). After Vandal attacks Kendra and Cisco, they turn to Barry for help. Realizing how dangerous Vandal is, Barry takes Kendra to Star City and asks Oliver and team to hide her until he can figure out how to stop Vandal. However, things quickly go from bad to worse when a man with wings AKA Hawkman (guest star Falk Hentschel) shows up and flies off with Kendra. Meanwhile, Harrison develops a serum to make Barry run faster and asks Jay (guest star Teddy Sears) to test it out."

The Flash/Arrow Crossover Part 2 titled Legends Of Yesterday - on Arrow season 4

"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."

Legends Of Today and Legends Of Yesterday air on The CW on 1 December and 2 December 2015, respectively.