'Arrow' season 4 episode 8 spoilers: Team Arrow and Team Flash join forces to create a weapon that would destroy Vandal in "Legends of Yesterday" crossover episode

Cast Members Stephen Amell, Right, And Katie Cassidy Attend A Panel For 'Arrow.' — Cast members Stephen Amell (R) and Katie Cassidy attend a panel for "Arrow" during the CW television portion of the Television Critics Association summer press tour in Beverly Hills, California July 30, 2012. Reuters

A new episode of “Arrow”, titled “Legends of Yesterday,” is set to air on Dec. 2, 2015 on the CW. It will be a crossover episode with “The Flash”, and will feature the two superheroes together.

“Legends of Today” is Season 2 Episode 8 of “The Flash,” while “Legends of Yesterday” is Season 4 Episode 8 of “Arrow.”

Spoiler alert! This article contains "Arrow" season 2 episode 8 spoilers.

The episode of “The Flash” is titled “Legends of Today.” The story will be the second major crossover event between the two DC superheroes, writes Screen Rant. Vandal Savage (Casper Crump) arrives in Central City and focuses on Kendra Saunders (Ciara Renee). Vandal attacks Kendra and Cisco (Carlo Valdes), who run to Barry (Grant Gustin) for aid. Barry accepts their request and brings Kendra to Star City, asking Oliver (Stephen Amell) and his team to keep her hidden until he finds out a way to stop Vandal. However, Hawkman (Falk Hentschel) arrives and flies off with Kendra. In the meantime, Harrison (Tom Cavanagh) creates a serum that allegedly makes Barry run faster. He asks Jay (Teddy Sears) to test it first.

“Legends of Today” is directed by Ralph Hemecker and written by Greg Berlanti and Andrew Kreisberg. It is set to air on Dec. 1, 2015 on The CW.

The “Arrow” half of the crossover, titled “Legends of Yesterday,” will feature Oliver and Barry taking Kendra and Carter Hall to a remote location to supposedly hide them from Vandal. Malcolm fixes a meeting between Vandal, Green Arrow and The Flash, which will not go as planned. In the meantime, Thea, Felicity, Laurel and Diggie collaborate with Team Flash to create a powerful weapon that can destroy Vandal.

“Legends of Yesterday” is directed by Thor Freudenthal and written by Greg Berlanti and Marc Guggenheim. The episode will air on Dec. 2, 2015 on The CW.

Vandal Savage is expected to be the main villain in the upcoming series, “Legends of Tomorrow,” which airs on Jan. 21, 2016 on The CW. The crossover episode is said to prepare for Season 1 of “Legends of Tomorrow,” setting Vandal as a powerful supervillain that requires a team of heroes to potentially defeat.

Stephen Amell was also at Heroes & Villains Fan Fest and said that he has no idea who was in the mysterious grave in the flash forward in the premiere episode of “Arrow” Season 4, writes ComicBook.com. He said that the dead person who someone he cared about and the one he wanted to kill was male.

Watch the trailer for “Arrow” season 4 episode 8 here.