Amazon dropped the full fourth season of The Expanse today, which means that enterprising fans of the series will have it binged by day’s end. They may also notice that while Season 4 encapsulates James S.A. Corey’s Cibola Burn — the fourth novel in the series that’s almost a bottle episode of a book — it has plenty of other stories to tell in order to keep the rest of the characters in the show involved.

Speaking to EW, showrunner Naren Shankar explained where the fourth season’s additional material came from and why it needed to pull from outside sources. One important element behind the season’s scripting was the confirmation of a fifth season on the horizon. Knowing that there’s more to come meant planting seeds that could bloom beyond the scope of Ilus and its colonial dispute.

“With Cibola Burn, the issue was the book is essentially a one-off, right?” Shankar said. “It’s entirely set on this alien planet. It only has a tiny bit of a prologue and an epilogue that’s back in the solar system.” Solving that problem meant looking beyond the scope of the book. “Book 4 extends across Season 4, but we created material that bridges book 4 into book 5,” the showrunner explained. “So there’s new material that deals with stuff that’s happening back on Mars, on Earth, in the solar system, in the Belt, that sets up things for the next season. And we incorporated Gods of Risk, which is the novella that’s set on Mars, into the narrative as well.”

Gods of Risk, released in between the second and third books, finally takes fans to Mars proper. Shankar noted that his team “took the events of Gods of Risk, and we shifted the perspective probably more onto Bobbie to tell that story through her” — a storyline he promises has “great ramifications going forward for the rest of the series.”

That series is already looking forward to its fifth season (thanks to its setup with Naomi’s ex, Marco Inaros, a major character in the fifth book) and beyond. A looming three-decade time jump is on the docket for the books, and Shankar is ready to face it.

“We have actually talked about it, and I’m confident we can pull it off,” the showrunner said of the 30-year hop. “I’m not sure I could say more than that, but I am confident that we can pull it off. It’s a really unique thing, and it is what I love about these novels and this adaptation is you get to do things that you generally don’t get to do.”

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