After a two-week break "The Flash" season 2 returns with the first part of a two-episode crossover with "Arrow." The first part will be seen on "The Flash" season 2 episode 8 while the latter half will debut on "Arrow" season 4 episode 8.

The episode that will air on "The Flash" is titled "Legends of Today" while the second half on "Arrow" is titled "Legends of Yesterday," both significant nods to the upcoming spin-off series "Legends of Tomorrow." The title of the crossover episodes as well as the synopsis reveal they are both introductions to the spin-off series.

According to the official synopsis, "Legends of Today" will start off with Kendra (Ciara Renee) and Cisco (Carlos Valdes) going out for another date when they are attacked by a man named Vandal Savage (Casper Crump). Back at STAR Labs they seek Barry Allen aka The Flash (Grant Gustin) for help but the latter informs they will need back-up.

Barry then calls in Oliver Queen (Stephen Amell) and the rest of Team Arrow. The whole team is seen in action with Cisco and Felicity Smoak (Emily Bett Rickards) working on a technical side, Laurel aka Black Canary (Katie Cassidy) and Thea Queen aka Speedy (Willa Holland) helping in alongside Malcolm Merlin (John Barrowman) and Diggle (David Ramsey). 

As seen in the promotional trailer, however, Oliver only has more bad news as he informs the group that Vandal Savage is in fact an immortal. Fans looking forward to "Legends of Tomorrow" will recall Savage is set to be the spin-off series' main antagonist.

Also introduced in the crossover event is Hawkman aka Carter Hall (Falk Hentschel). He will already have a strong relationship with Kendra, who is in fact Hawkgirl, and both will recognize Team Flash and Team Arrow as a group of heroes instead of labeling them as enemies.

"The Flash" season 2 episode 8, "Legends of Today" airs this Dec. 1.