The Mandalorianis going to fundamentally change the Star Wars universe — and not just because it’s the very first live-action Star Wars television show.

According toThe New York Times,The Mandaloriancontains a “Star Wars universe spoiler” so big that Disney is going all-out to keep it a secret. While critics will receiver full screeners forother Disney+ original series, the first episode ofThe Mandalorianwon’t be available in its entirety until November 12, when Disney+ launches for the general public, in an attempt to keep the plot twist under wraps.

As a workaround,Entertainment Weekly reports that critics have seen a half-hour compilation of clips from the show, which have been carefully selected to avoid spoilers. So far, the reviews are excellent.

The Mandalorian‘s galaxy-changing revelation isn’t the only mystery surrounding the series, either. Earlier, the officialStar Wars Twitter accountrevealed a new set of posters featuringThe Mandalorian‘s main cast, including one character that hasn’t been shown in any ofThe Mandalorian‘s other promotional materials.

The posters offer our best looks yet at Gina Carano’s Cara Dune, a former rebel who’s become a mercenary after the end of the Galactic Civil War, and IG-11, a deadly assassin droid. They also feature striking new shots of Pablo Pascal’s armor-clad Mandalorian and Carl Weathers as Greef Carga, leader of a local bounty hunter guild.

The fifth poster, however, has someone new: A grizzled alien sporting goggles. Many fans assume that the creature, which is known in the Star Wars world as an ugnaught, is the character played by three-time Academy Award nominee Nick Nolte, who has been officially announced as part ofThe Mandalorian‘s cast but who hasn’t appeared in his regular, human form in any trailers or TV spots.

The Mandalorianis the flagship launch title for Disney+, Disney’s brand new streaming service. In addition toThe Mandalorian, Disney is preppingtwo other live-action Star Wars showsfor Disney+, a revival of the award-winning animated seriesThe Clone Wars, and a number of behind-the-scenes documentaries. Original series based onthe Marvel Cinematic Universeand Pixar films are also in-production for the service, which will come witha deep library fullof Disney’s older movies and television shows.