Sure, I'll Read This Old Guy's Diary
The exposition begins when the unnamed author agrees to read some senile guy's journals as a favor to the director of a retirement home. In this way we are tangentially introduced to our protagonist, Will Henry the journal writer, as well as the method of storytelling we are about to enjoy.
Invasion of the Man-Eaters
The rising action starts when Erasmus Gray shows up at Dr. Warthrop's house with a half-eaten corpse and a dead Anthropophagus. (Gee, thanks?) From there the doctor and Will Henry engage in several encounters with the terrifying man-eaters, and are forced to assemble a team to combat them.
Everything leads up to the battle of Dr. Kearns and his "Maori Protocol" versus the diabolical Anthropophagi. Will the headless gluttons defeat our brave protagonists? Or will the noble Will Henry save the day? And how will they kill the alpha female without Sigourney Weaver's help? (Just kidding—Sigourney Weaver totally isn't in this book.)
Luckily the good guys win. Otherwise the book would end right here, right now.
Take That, Evildoers
Now that the scary monsters have been defeated, in the falling action we see Dr. Warthrop, Will Henry, and Dr. Kearns travelling to Motley Hill to finally get to the bottom of the mystery regarding how the Anthropophagi got to New Jerusalem. And in an unexpected yet satisfying twist, we also see some nasty people get their comeuppance. All is right in the world… for now.
Wait, Could This Be Real?
The resolution of our story brings us full circle back to the author who has been reading and transcribing Will Henry's journals. He is skeptical about what they contain, but when he visits Will Henry's grave he finds a worm that may or may not verify all the strange events he has related. Thanks a lot, Yancey—we were just thinking it was safe to sleep at night.