I'm releasing the final three chapters all at once because, as I'm sure you noticed at the end of chapter 22, the end of the story is quite dark. I hadn't wanted to leave the readers dreading each additional chapters, so I figured it would be easier reading them all at one sitting. However, if the story gets too much for you and you decide to quit it, don't skip the Epilogue (chapter 25). As expected, that details what happens after everything else, and it sets the stage for the rest of the story.
When I wrote this, in fact, when I first thought up the story, I had this ending in mind, though I'd meant to simply end the story here, with the rest of the story, what happens afterwards, undefined. I'd felt I'd told my story, about what happened to David and his group, and that what happened afterwards wasn't as important. The important thing was addressing what no one else ever did, that is, facing the unimaginable, the death of everyone and everything around you. I figured that there were plenty of Post-Apocalyptic stories that details what happens afterwards, and that I didn't need to cover that same territory, even if this version set up a unique storyline.
However, after I finished it, and thought about it, I saw that this story naturally led in a whole new direction, given me yet a new story to tell. So I've started a sequel, "Grappling with Survival", that details how the world deals with survival after having what they did in this book. That twist, which one can only appreciate from starting the post-apocalyptic tale with this story, provides a whole different scenario than one normally finds in the genre, and I wanted to explore it. In this next book, it isn't a fight between the good guys and the bad guys, each trying to build their own armies using the remains of society. Instead there aren't many remenants, and instead of fighting with one another, everyone is too fed up with death, from watching their friends, neighbors and family die, that they can't picture killing each other. Instead it becomes a matter of survival. Between people choosing to hide from the Great Death, and those choosing to continue living, despite the risks.
So I hope you'll join me in the exploration and read it when it's done. Unlike this book, it won't be anywhere near as dark. There will still be the occasional death, but the whole tenor has changed, and it now focused on surviving and continuing on, in spite of everyone else.
Note: If you couldn't finish this story, don't worry, you can continue the next story without having finished it, and it won't pose the same problems that this one did.