Sneak peak of 'The Flash'/'Supergirl' crossover – why it's happening on CBS

Supergirl and the Flash will appear in the same TV episode later this month. The superheroes' TV shows air on CBS and the CW, respectively.

A quick promo, as befitting one of the speedy superheroes who appears in it, has been released for an upcoming TV episode in which Supergirl (Melissa Benoist) and the Flash (Grant Gustin) meet.

What's unusual is that these two superheroes are from rival TV broadcast networks.

On March 28, Barry Allen, also known as the Flash, will pop up on an episode of the CBS program “Supergirl.” The shows about the superheroes air on different networks, but both Supergirl and the Flash hail from the world of DC Comics.

The preview shows the Flash zipping around a Supergirl logo and Supergirl arriving in front of him.

The Flash is no stranger to intra-network crossovers, with the superhero Arrow (Stephen Amell) having appeared on “The Flash” and the Flash appearing on the Arrow’s self-titled show, which is also on the CW. 

Both “The Flash” and “Supergirl” are relatively new shows, with “Flash” having debuted in 2014 and “Supergirl” having appeared this past fall.

Why is the CW's Flash traveling over to CBS and not vice-versa? 

Forbes writer Alisha Grauso posits that CBS may be hoping to bring viewers from “Flash” over to its own superhero show. In February, a “Flash” episode drew more viewers between ages 18 and 49 than network shows like Fox’s “New Girl” and ABC’s “Fresh Off the Boat.” 

"The crossover may just ensure that ‘Supergirl’ gets a second season,” Ms. Grauso writes. “…Linking Supergirl to the [‘Flash’/’Arrow’] verse, however tangentially, will at least guarantee a major jump in ratings for an episode that will find fans of Grant Gustin as the Flash loyally tuning in.”

Why are young viewers tuning in for “Flash”? 

One reason is that the CW has traditionally been the home of a younger viewer than others broadcast TV networks. As of last year, the CW had the lowest median age for viewers (46.6 years old), years below the second-youngest, Fox, which has a median viewer age of 50.5. The CBS median age? 59.9.

The CW has successfully brought in different viewers with shows like “Arrow” and “The Flash,” writes AdvertisingAge writer Jeanine Poggi. 

“The CW has spent several years revamping its image with a slate more heavily skewed toward supernatural, sci-fi and superhero themes, including shows like ‘Arrow,’ ‘The Flash’ and its newest addition, ‘iZombie,’” Ms. Poggi writes. “…These series have successfully attracted both an older, broader audience, as well as more male viewers.”

And why do viewers like “Flash” in particular? Vulture writer Simon Abrams called the program “the best superhero show on TV” in 2015. (And that’s in a TV landscape where big networks like ABC, CBS, and Fox all have at least one.) 

“[The show has] a hero distinguishable from Batman … That may not sound like an issue, but it’s one that many talented creators struggle with,” Abrams wrote. “…One of the most exciting things about The Flash is it's clearly created by people who know that people read superhero stories for the supervillains … There's also a corny but solid sense of community … You grow to care about The Flash's characters.”