The CW Is Shaking Up This Year's 4-Show DC Superhero Crossover

Last year's team-up drove the network's most-watched week ever

After its annual crossover of all its DC superhero shows yielded the highest ratings in CW history, the network is shaking things up a bit for this year’s big team-up between the casts of Arrow, The Flash, Supergirl and DC’s Legends of Tomorrow.