“Gone Girl” was awesome, but I can’t tell you why. Gillian Flynn’s new novel was darkly comic, deliciously entertaining, ridiculously addictive and downright messed-up, but I can’t tell you why. Seriously. To give away the shocking plot twists and titillating psychological thrills would just be criminal.

It looked like Nick and Amy Dunne had it all. They were the “happiest couple on the block,” both attractive and charming. When they first met, both were successful writers in New York City. Amy, a wealthy socialite, and Nick, a dashing poor kid on the make, fell for each other in a way that seemed too good to be true. Their life together was perfect until, in a distinctly modern way, disaster set in. 2008 arrived, and with it, the Great Recession.

Newly unemployed, Nick and Amy move back to Nick’s hometown, North Carthage, Missouri. North Carthage is a quintessential Mississippi River town, rife with broken dreams and unemployed hobos. Nick borrows the last of Amy’s trust fund to start a bar with his twin sister, Margo (whom everyone just calls Go). Nick is also forced to care for his beloved, dying mother and his hated, dementia-addled father. Amy, meanwhile, stays home, adjusting to a Midwestern life of potluck dinners, Wal-Mart and sheer boredom.

One day, Nick arrives home, to find — Oh, God no! — Amy is gone. The front door of his house is “wide-gaping-ominous” open, and the living room is torn apart. Panicked, shocked, terrified, Nick calls the police. It’s only a matter of time before he seems to become the prime suspect.

The evidence mounts convincingly against Nick. Where was he the morning of? Why does the crime scene seem so staged? Doesn’t Nick benefit financially if Amy is out of the picture? Why is there a giant pool of Amy’s blood that someone sloppily attempted to mop up — like an incompetent husband might do? And, of course, isn’t it always the husband? It doesn’t look good for Nick, and his utter inability to appear sad about his wife’s disappearance does not play well on television. Nick-the-pariah is on a slow march to jail, and Amy is nowhere to be found.

Here’s the thing: There is this absolutely, unbelievably, earth-shatteringly twisted plot twist. Actually, there are several. But one of them is a real whopper. Real M. Night Shyamalan material. Obviously, I can’t tell you what it is; I guess you’ll have to trust me. It’s simply — how should I put this — to die for.

“Gone Girl” is told in two voices— Nick’s and Amy’s. Nick narrates the present day; entries from Amy’s diary depict the couple’s past. The two perspectives intertwine, complementing (and often contradicting) each other, but a chilling tale begins to emerge. Nick and Amy were not the happy couple they appeared to be.

The two narratives depict a marriage falling apart — misunderstandings, passive aggression, outright aggression all strain the once happy life Nick and Amy shared. Nick feels guilty about dragging Amy to North Carthage, guilty about failing to provide for her, guilty about not being as perfect as she is, terrified about becoming his emotionally abusive father. Amy, on the other hand, tells a heart-wrenching story about failing to live up to impossible personal (and parental) expectations, dying of boredom in a lonely house, increasingly isolated from her distant and moody husband. Both spouses are trying, but the marriage is just not working. And then Amy is taken.

Yet all is not as it seems.

There is something darker and more insidious about the whole situation. Colorful, comical and creepy characters from Nick’s and Amy’s past emerge to call into question everything we believe about the young couple. Why does the evidence so overwhelmingly point to Nick? What does Nick have to hide? And, above all, where is Amy — the gone girl? Is she even still alive?

Since I’ve mentioned there is going to be this crazy twist, you might be tempted to spend the whole book looking for it. That’s O.K. — that’s what I did (I had been forewarned). Let me give you a piece of advice: “Gone Girl” contains several twists. If you are going to spend the whole book waiting for the big one, you might wrongly think you’ve reached it. You probably haven’t. Unless you are positive, beyond a shadow of a doubt, that you’ve reached the game-changing twist, you won’t fully realize how deliciously messed-up the whole book is. Critics may whine that “Gone Girl” is not the most realistic thriller. It doesn’t have to be; it is engaging enough to cancel out its lack of reality.

Darkly comic, sickly engrossing, charmingly well-written, “Gone Girl” is murderously good. Un-put-downable.