In the debut season of Supergirl, we saw the Flash entering the National city, jumping parallel dimensions and breaking time-space continuum. At the Paley fest, Greg Berlanti (the executive producer) stated that Flash is the perfect DC Superhero to come into Supergirl universe. He said “We needed to create a way to do it. We had to introduce Superman since you’ve heard about him and you’ve heard about who Supergirl is, but in the world of Arrow and Flash, they don’t exist. We introduced the Multiverse in Flash and that was always our way in”. Apparently, there are many earths co-existing in the grand scheme of things. On Kara’s earth, there is a Central city but without Star Labs, Barry, Cisco, Caitlin, Iris West, Green Arrow, Black Canary etc.
In the episode, we saw both of them trying to outdo each other in a race, they took down Silver Banshee and Livewire. Flash is seen wearing Tachyon device similar to the one donned by Reverse Flash in season 1. He helped Team Kara to develop a way to keep meta-humans locked up so that they don’t need to take them to DEO every-time. Instead of calling him the Flash, they used “The Blur” which is what they called Clarke in “Smallville”. This particular episode saw the maximum TRP in the entire season which basically confirmed that Supergirl and Flash is a winning combination and has a stamp of approval from DC fans.
This time, they are planning for a special 2-part musical crossover which will join the mega CW-DC Crossover of superheroes. Greg Berlanti, the executive producer, said during the Television Critics Association press tour that “they’re going to be mostly preexisting songs, they’re going to try and include at least one original song per episode, and the two episodes will likely air sometime in the back half of the year.” Both Melissa Benoist and Grant Gustin have musical backgrounds as both the actors have appeared in “Glee”. Jesse L. Martin (Joe West) played the role of Tom Collins in Rent on Broadway, while Jeremy Jordan (Winn) appeared in Broadway production of Newsies and film version of “The Last Five Years”.