Warning: SPOILERS ahead for the Preacher comics.
Preacher is back for a final season, and it's leading up to one of the best scenes from the comics - when Jesse Custer gets thrown out of a plane. Preacher season 4 has been confirmed to be its last, and this means that it's time for Jesse, Tulip, and Cassidy to wrap up their journey across the world in search of God. This is definitely a series leading up to a big finish, and from the first few episodes of season 4, it looks like the show will find its way back to its comic origins for the same type of ending.
For the most part, Preacher so far has deviated quite a bit from the source material. The broad strokes are still there - the three main characters, Genesis, the Saint of Killers, the Grail (and Humperdoo), and a road trip in search of God - but much of the plot itself is totally new. Some fairly large chunks of the original comic series have yet to make an appearance as well (and aren't likely to). This isn't a bad thing, of course, but the Preacher season 4 premiere shows that things are going to go back to the books for the final season - including the pivotal scene were Jesse falls from an airplane and loses an eye.
"Masada" begins with a flash-forward, to Tulip and Cassidy (a bleach-blonde Cassidy, who looks significantly more like his comic counterpart than he has in the past) hanging out, then making out. From this shocking scene, the episode cuts to the Australian outback - and to Jesse falling out of the sky from an airplane, to land in the desert, presumably dead. This is just a hint of what's to come, but comic readers know everything that has happened here. In the comics, Jesse, Tulip, and Cassidy are on a plane trying to escape the Grail, when Jesse is knocked out the open door by the concussive blast of an explosion (the Grail trying to nuke the Saint of Killers). Cassidy catches his hand, but putting his arm out the door means that it catches on fire from the sun, and Jesse uses Genesis to force Cassidy to drop him - most likely to his death.
The scene in "Masada" looks to be exactly like the one in the comics: Jesse's fall from a plane, and there's a mushroom cloud of an explosion nearby. This plane, then, wouldn't be the one that takes Jesse to Australia, because that doesn't have either Tulip or Cassidy on board. Instead, it's likely that they will follow Jesse to Australia, and it's there that everyone (the Grail, the Saint, and the Trio) will come together for a final showdown. Furthermore, the scene in the comics also includes Jesse's final meeting with God - and the loss of his eye, as God goes from loving to vengeful and eats Jesse's eye out of his head. The comics then see Tulip and Cassidy get together under the assumption that Jesse is dead, much like the scene that opened Preacher season 4.
While this is an epic scene - one that unfolds slowly in the comics - and fans can look forward to seeing Jesse force Cassidy to drop him out of an airplane, there are going to be some major changes from the source material. For one, this scene originally happens around midway through the comic story, not at the end. The final showdown between the Grail, the Trio, and the Saint is going to have different motivations, and the survivor count may well change, too. This scene is also unlikely to be the final scene of the series; like the comics, Preacher will presumably end with a tragic dust-up between Cassidy and Jesse, after Jesse comes back alive from his fall. Although given that the scene between Cassidy and Tulip saw him encouraging her to drink less, the reasons for this may also change in a major way.
Cassidy is a far more sympathetic character in the Preacher show (damaged as he is), and it will be interesting to see if the series keeps his final sacrifice intact, even if they do change his final fight. With so many changes since Preacher season 1, it's difficult to predict exactly what will happen, but comic fans can be happy that, even if everything else changes, the eye-patch as well as the scene with God are certainly going to make onto the small screen.