Here's how I'm going to make my fortune: I'm writing an unauthorized sequel to John David California's unauthorized sequel to J.D. Salinger's The Catcher in the Rye. My book will turn the Holden Caulfield series into a trilogy! It's what the kids nowadays are calling a mash-up, combining characters from The Catcher in the Rye with plot elements from Invasion of the Body Snatchers. I'm calling it The Snatcher in the Rye.
The plot: Holden Caulfield has finally realized his dream of working in a big field of rye where children are playing. His job is to catch them before they fall off a nearby cliff. It doesn't pay much, but since there aren't a lot of employment opportunities of this sort, Holden considers himself lucky to have it.
One morning Holden notices that overnight, crop circles have appeared in the field of rye. He soon learns that these elaborate designs are a message from an alien race! They come from a planet almost exactly like earth, except on their planet they don't have to dial '1' when making a long-distance call. Turns out these aliens do all their writing in crops. A field of grain is their preferred medium for writing and information storage, and they have long since run out of room on their own planet, even with abridgements. They picked up an old radio broadcast from earth that mentioned "amber waves of grain," and have come looking for something to write on.
Holden tries to convince the authorities that the crop circles are an advance warning of a secret alien invasion. No one will listen to him, mostly because they can't understand why anyone would give advance warning of an invasion if it's supposed to be a secret. Holden is further hampered in his efforts by the fact that he's about 103 years old. Even kindly Dr. Miles Bennell won't listen because he's too busy hitting on Becky Driscoll.
Back at the crop field, Holden finds strange seed pods growing amidst the rye. They soon turn into exact duplicates of the children, who are then replaced by their emotionless alien doppelgangers.
The story ends with Holden running into traffic in the middle of the Interstate screaming, "They're phonies! All of them! Can't you see? They're all a bunch of goddam phonies!"