Batman: The Killing Joke is one of the most famous one-shot comic storylines in superhero lore. First published in 1988, Alan Moore’s dark, twisted comic both provided an origin story for Batman’s arch nemesis, the Joker, and pitted the two sides of the same chaotic coin against one another, while drawing a parallel between the two flawed men.

It’s a storyline that has influenced nearly every director of Batman’s various incarnations in the years since it was published. But the storyline has never been adapted into a feature film — until now. DC and Warner Brothers Animation are releasing an animated feature based on the film, which could be the most important addition to Batman’s legacy we see this year. Mark Hamill has come out of retirement to voice the Joker, reprising the role that made him famous and beloved, far beyond his initial Star Wars fame.

While the comic is short, the trailer shows that the film will expand on Batgirl, a.k.a. Barbara Gordon’s backstory and impact on the events of The Killing Joke. The original comic sets up the Joker as a tragic character, whose response to past trauma provokes a reaction violently different from the Dark Knight’s. The Joker focuses his insanity on commissioner Jim Gordon, attempting to drive him mad through emotional and physical torture to both Gordon and his daughter Batgirl. Needless to say, this isn’t an animated film for children — the MPAA has already assigned the movie an R-rating.

Unfortunately, early commenters are already noticing that the animation quality isn’t top-notch. After years of anticipation, it’s sure to disappoint many fans if the visual work isn’t up to par with the voice acting and source material.

Watch the full trailer below.