The end of Star Wars: The Last Jedi is, against all odds, filled with hope. Despite all the losses suffered throughout the movie—a trend which started, arguably, with the death of Han Solo in 2015’s Star Wars: The Force Awakens—the narrative ends with a promise to rebuild, to keep fighting, to go on.

And the reality outside of a galaxy far, far away means that promise can never be fulfilled; without Carrie Fisher, the future teased in The Last Jedi simply can’t happen. So what will unfold in its place?

There should be no denying that The Last Jedi ends in a place where Leia Organa is central to the Star Wars mythology in a way that she’s never been before. First of all, the story requires Kylo Ren (Adam Driver) to face off against—and, presumably, attempt (and fail) to kill—his mother in the final act of the trilogy, after two episodes where he kills his father and surrogate father. But beyond that, there’s also one of the most important lines of Last Jedi, where Finn tells Poe not that people believe in their cause, but that they believe, specifically, in Leia. The final time we see the Resistance, Leia is literally at the center of it all.

(This is to say nothing about the fact that Luke telling Kylo that even if he dies, he would not be the last Jedi, could be a misdirect and actually be about Leia instead of Rey. Leia, let’s not forget, survived in the vacuum of space by the Force alone earlier in the movie; all Rey did was move some rocks.)

All of this means that Episode IX will have a very clear hole at its heart, in whatever form it eventually takes. It’s already been announced that Leia will not be digitally resurrected by Lucasfilm for the final movie in the sequence following Fisher’s death, meaning that the character who has come to personify the heart of the new trilogy will be present only in her absence, which is sure to fill every space of the movie.

Storytelling, like both nature and Leia herself, abhors a vacuum, however, and it’ll be interesting to see what replaces Leia in Episode IX. Can Rey take the place of Leia when it comes to a potentially redemptive figure for Kylo Ren, given that she’s already failed in that position? Could Poe become a figurehead for the Resistance in the absence of Leia? (I fully expect Leia’s spirit to be evoked continually by whoever steps into that role, nonetheless.) And who, if anyone, will become the trusted elder advisor at this point? Luke’s Force Ghost, perhaps…?

All of these solutions will be stopgaps, ultimately; something The Last Jedi does, perhaps unintentionally, is emphasize how much of a generational story the new trilogy is. The original trilogy had that as subtext—the child fighting, and eventually redeeming, his father—but so much of the current trilogy is about the passing of the torch and dealing with decisions (and mistakes, and troubled relationships) of your parents and the parents of those around you.

Having Han, Luke and Leia there has been integral to that, as it’s shown how the ghosts of the past affect those responsible. The dialogue between Leia and Laura Dern’s Holdo, where the two talk about having lost too many people, is something that only works coming from an older character, not to put too fine a point on it. And without Carrie Fisher, there literally is no familiar character to fill that space anymore. Through no fault of anyone or anything rather than nature, one of the primary thematic arcs of the trilogy is severed right when it should be coming into focus.

Star Wars is a story in which death has been shown to be important, but not necessarily final—as can be seen by The Last Jedi’s cameo from Yoda, if nothing else. But in the real world, that’s sadly not the case, and Carrie Fisher’s death has left filmmakers with a particular problem: What do you do when the ending that everyone wanted isn’t actually possible anymore?