On an early October afternoon, the casts of The CW’s “Arrowverse” serials gathered in an airport hangar on the outskirts of Vancouver B.C. for a historic event. FromArrow, there was Stephen Amell (Oliver Queen, aka the show’s emerald archer), David Ramsey (Diggle/Spartan), Willa Holland (Thea Queen/Speedy) and Emily Bett Rickards (Felicity Smoak). FromThe Flash, there was Grant Gustin (Barry Allen, aka the show’s scarlet speedster), Candice Patton (Iris West), Tom Cavanagh (H.R. Wells), Danielle Panabaker (Dr. Caitlin Snow) and Carlos Valdes (Cisco/Vibe). FromLegends of Tomorrow, there was Brandon Routh (Ray Palmer/The Atom), Caity Lotz (Sara Lance/White Canary), Dominic Purcell (Mick Rory/Heat Wave), Franz Drameh (Jax, one half of Firestorm), Victor Garber (Dr. Martin Stein, the other half of Firestorm). And fromSupergirl, there was the maiden of might herself, Melissa Benoist, the only actor dressed in their caped crusader colors. (Must be dry cleaning day at the Hall of Justice.)

Calling this unprecedented all-star squadron of comic book stars to order, director Dermott Downs instructed them to perform a very important heroic duty: Surprising Benoist with a “Happy Birthday” serenade. “That was overwhelming,” says the actress, who turned 28 on the day in question. “I think that will be the first and only time I will be sung to by a group of superheroes.” Of course, Benoist and all of her Super-Friends had to actually work on her birthday; not even the girl of steel gets a day off for turning another year older. The occasion of this massive team-up: filming a four-show crossover event, which begins in the final scene of the Nov. 28 episode ofSupergirl and unfolds over the next three nights in episodes ofThe Flash, Arrowand Legends. Entertainment Weekly visited the set of the massive undertaking and brings you a report in our new issue,on sale this week. We got to see Supergirl fly, The Flash and Cisco tear a hole in the fabric of space-time (or pretend to), and even saw someone get shot.No, we can’t tell you who, but we can tell you the threat that set the sprawling plot in motion: The Dominators, mind-controlling extraterrestrials threatened by Earth’s surging population of metahumans. If you’re wondering if “mind-control” = “we’re totally going to see these superheroes fight each other,” then you’re absolutely [REDACTED].

The “Arrowverse” has an alternate moniker, the “Berlantiverse,” named after the super-producer who presides over it, and he has some feelings about the term. “I object to it, to be honest. There are just so many people that are also part of this,” says Greg Berlanti, 44, whose prodigious, eclectic output began withEverwood in 2002 and currently includesBlindspot on NBC. “Plus, you never want anything named after you that people could be upset or angry about.” Produced in collaboration with Marc Guggenheim and Andrew Kreisberg, Berlanti’s small screen treatment of Warner Bros.’ DC Comics properties offers an alternative – some might argue correction – the studio’s big screen superhero pop, including the apocalyptic heavy metal of Zack Snyder’s Man of Steel flicks and the bubblegum nihilism of David Ayer’sSuicide Squad. The Arrowverse actually likes superheroes, believes in superheroes, and knows how to have fun with them – and critique them – without deconstructing them to smithereens.They possess the levity of Marvel’s cinematic universe (still the genre’s gold standard), and the progressiveness of Marvel’s best TV offerings (Jessica Jones, Luke Cage), but with a more carefree embrace of melodrama and whimsy.

“These shows have to work on multiple levels,” says Berlanti. “You want them to be fun and enjoyable. But if they’re not about something, why are you showing up to work every day and asking everybody to pour their heart and soul into a story if it’s only about the Flash fighting a villain of the week?”

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