Batman: Gotham by Gaslight is the latest DC animated movie, and it’s one that fans have been waiting for. Based on a 1989 comic by Brian Augustyn, Mike Mignola, and P. Craig Russell, which told the story of an alternate reality, where Batman operates in the Gotham City of 1889, and who has to contend with one of the most famous supervillains in history when Jack the Ripper comes to town.

Back in October at New York Comic Con, we spoke with the writer tasked with adapting Batman: Gotham by Gaslight for the screen, Jim Krieg, as well as executive producer Bruce Timm about the challenges of bringing such a beloved Batman story to life, how they fleshed out the story, and what role Sherlock Holmes has to play in the whole process.

“Gotham by Gaslight is one of the most popular graphic novels in our library,” Jim Krieg said. “This one has been on top of the list for a long time. And nobody had to twist our arms to do it. When it came up we were all happy to take it on.”

Bruce Timm admitted that Gotham by Gaslight was a tougher sell to the higher ups at Warner Bros. than some of the other animated adaptations. “This has come up several times in the past and there’s maybe even been a little bit of reluctance to do it because it is a period piece, and it takes place in an alternate timeline,” Timm said. “But for some reason we brought it up again and everybody said, ‘oh yeah, let’s do it.’ So, I didn’t have to pitch it very hard.”