On the big screen, DC Comics superheroes Batman and Superman are battling one another – but on TV, two other DC costumed superheroes, Supergirl and The Flash, are making nice. So much so that they’re appearing together tonight in a crossover episode that manages to cross over two different networks. Greg Berlanti is executive producer of both CW’s The Flash and CBS’s Supergirl, and both Grant Gustin (The Flash) and Melissa Benoist (Supergirl) worked together on Fox’s Glee, so that was easy enough. But what’s nice is that these two shows are lighter in touch than the current cinematic DC Comics, and their overlapping-universes story line allows them to meet, confine in, and even challenge each other. And yes, there is indeed a footrace between Supergirl and The Flash. Ready, set, gone!