Not long ago, Stephen King shared a teaser photo from The Dark Tower that hinted at a potentially huge game-changer for the long-developing film adaptation. The TL;DR version: It’s not an adaptation, necessarily, but a sequel. To explain exactly why that is would be to get into book spoiler territory, so I’ll save that for later in this post. For now, director Nikolaj Arcel has confirmed our suspicions about that photo and what it means for Roland’s quest in The Dark Tower.

EW’s coverage of The Dark Tower continued with a new behind-the-scenes photo (above) and some insight from both Arcel and King himself. As for King’s involvement with the adaptation, the author says he offered suggestions, but ultimately left it up to Arcel:

I’m 100 percent behind it — which doesn’t mean it necessarily will work, just that it’s a good way to try and to get into these stories.

And what “way” would that be? Well, for starters, Susannah and Eddie Dean won’t be joining Roland’s Ka-tet (a group of people bound together by fate, or Ka) — at least not in this film, though it may allude to them at some point.

But the more notable — and exciting — part of Arcel’s approach is what many fans had already assumed based on that photo Stephen King shared a while back. Arcel confirms to EW that The Dark Tower essentially functions as a sequel to the books, adding “It has a lot of the same elements, a lot of the same characters, but it is a different journey.” How so? Basically by providing an alternate version of events…well, technically. It’s a brilliant play in that it allows people who haven’t read the books to understand the story, though it may resonate more with established fans. It also allows Arcel to justify some of the bigger changes in characters and plot.

If you haven’t read the books and still plan on doing so, this is where we get into spoiler territory.

Still here?

In King’s story, Roland is on his epic quest without a key item: The Horn of Eld, an object he left on a battlefield long ago despite a friend’s warning. When Roland reaches the tower in the seventh book, the story comes to an end and Stephen King coyly implores the reader to stop there — but if you read on, Roland enters the tower and gets to the top, only to realize that he’s been on this journey many times before, and each time it ends in failure. When he wakes up, he’s back at the beginning with no memory of reaching the tower, but this time he has the Horn of Eld. The implication is that the next journey will be Roland’s last, and he’ll probably get things right this time around.

So that’s where we are with the film adaptation, in which Roland will be in possession of the Horn of Eld, signifying that Arcel’s version is actually a sequel — to us, anyway, since Roland has no idea he’s been on this quest many times before.

Roland’s final quest will begin when The Dark Tower hits theaters on February 17, 2017.