Ben Affleck’s solo Batman movie will remain a fascinating “What if?” in the annals of superhero movies. Affleck was attached to direct and star, but as the DCEU crumbled and fell apart, Affleck eventually departed the project, first handing directing over to Matt Reeves before leaving the role entirely where now a younger Robert Pattinson will wear the cape and cowl.

But what did Affleck have in store? His Live by Night cinematographer Robert Richardson was also attached to the project, and he’s recently been doing the rounds for Once Upon a Time…in Hollywood. On the HappySadConfused podcast [via The Playlist], Richardson revealed that Affleck’s Batman movie would have taken place inside Arkham Asylum, the institution for the criminally insane that houses the superhero’s rogues gallery when they’re not out doing crimes.

“He was going into the more insanity aspects…He was entering more into the Arkham, he’s going into where everyone was bad,” said Richardson. “That’s where we were going. I was very interested in that one.” But Richardson also notes, “There was a script, but not a loved script. There was a lot of work he was doing to it to change it.”

I think a Batman movie set in Arkham would be a nice change of pace for the franchise. Previous Batman movies have been largely about Gotham, and it makes sense because it’s large playground for the filmmaker (Burton, Schumacher) or it provides a metaphor for America (Nolan). But Arkham is, by its nature, claustrophobic, and it traps Batman inside with his foes. That’s part of what makes Batman: Arkham Asylum such a terrific video game.

We don’t know what Reeves has in store, but hopefully Affleck will go on the record some day to talk about his vision for what his solo Batman movie would have been and the obstacles in getting the script right.