when do the arrow and the flash crossover
Flash vs. Arrow "Flash vs. Arrow" is the first annual Arrowverse crossover event, broadcast on The CW, featuring episodes of the Arrowverse television series The Flash and Arrow. The event began on December 2, 2014, with The Flash episode "Flash vs. Arrow" and concluded the next day with the Arrow episode "The Brave and The Bold". The crossover sees Team Flash (Barry Allen / Flash, Caitlin Snow, and Cisco Ramon) helping Team Arrow (Oliver Queen / Arrow, Felicity Smoak, and John Diggle) take on the boomerang-wielding villain Captain Boomerang, while Team Arrow helps Team Flash confront the metahuman Roy Bivolo.