The Flash / Arrow Crossover Trailer is out watch below. Emergency Awesome (possibly the best YouTube channel in the world today) has a breakdown of the crossover mega-sode above! The breakdown covers the Legends of Tomorrow, Hawkgirl and Hawkman vs Vandal Savage, Arrow, Flash and much much more.
The Flash / Arrow Crossover starts with the Flash episode “Legends of Today” December 1 (USA) on the CW.
With the 2-part episode concluding with the Arrow episode “Legends of Yesterday” December 2 (USA) on the CW.