Sequels can be a tricky thing to write sometimes. Such projects can end up being a lesson in frustration when you realize that you haven’t really written a new story in the universe you’d created so much as you’ve just attempted to rewrite the original story again, and that can be a huge problem in itself.
I’ve been working off and on with a sequel to the Bridgetown Trilogy (which I’ve been referring to as MU4, as in ‘Mendaihu Universe Book 4’) and as tempting as it is for me to write another story about the dysfunctional shenanigans of Vigil or the PoeKaina and CarNando ships (heh) or whatever, that’s the last thing I should really be doing. That’s why one of the first rules I’d come up with when I first started playing with the idea was to have Book Four set seventy years after the events of The Balance of Light, ensuring the original cast was already in the past tense, at least in the physical sense. I had to come up with new characters, each with their own histories and drives, yet somehow tie it in with the Mendaihu Universe. That in itself wasn’t too hard, as I’d left myself wide open for all kinds of exploration in this particular world.
No, the hard part was how to tie it in with the original trilogy yet not write the trilogy again. So how do I do that?
With In My Blue World, I deliberately left the story open-ended to a degree that its main characters could go on further adventures with Zuzannah and the rest of the alternate universe gang. That kind of sequel is in a ‘continuing adventures of…’ format, such as Jim Butcher’s Dresden Files, or Martha Wells’ Murderbot Diaries. Conversely, Diwa & Kaffi evolved out of a world I’d already created for a multi-short story project involving different species of beings on a college campus, so that one will end up sort of going in reverse when I get to writing those stories. That format is simply standalone stories in a shared world.
So with MU4, I had to give everyone a new directive: it had to relate to the supernatural/spiritual goings-on in that world, with many of the rules that Denni/The One of All Sacred laid down by Book 3…and then twist them somehow. Historical knowledge tends to warp and evolve over the years; what really happens and what we want to remember can often be two completely different things, especially when spirituality and religion is involved. That ends up being the main rule of the new version of this universe: Bridgetown (and the world) is filled with loyal Followers of the One…yet do they truly follow the tenets Denni laid down so many years ago? And then follow it up by imprinting these new characters onto that rule and see where it goes.
There are many ways to go about writing sequels, and of course how you decide to write them totally depends on how you want to approach them. My favorite way, as you’ve noticed, is to keep my original stories open for such possibilities! My only caveat then is to keep a finite number of ground rules…and the rest is fair game.