The only way to appreciate “The Book of Henry” is by treating it as the movie equivalent of a summer read, a beach book that tries to pack in the full breadth of human experience into a few too many pages.

It’s got terror and tragedy, romance and charm, warmth and wit and a real page-turner of a plot. But every single one of those attributes is undercut by the fact that it aims to be the first “cute” thriller about child abuse, making it the most tone-deaf picture on that subject since “Radio Flyer” (Look it up).

Henry, played by the luminous Jaeden Lieberher of “St. Vincent” and “Midnight Special,” is a brilliant 11 year-old, a genius even.

“I prefer precocious.”

He’s so smart he trots out an impromptu discussion of our shared “existential crisis” for his fifth grade “My Legacy” writing project, but his teacher is always more impressed with his humanity.

He’s treated like an adult by most of the adults he knows, mom’s taunting waitress colleague (Sarah Silverman), for instance.

“Hello HANK,” she says, baiting him every time they meet.

“Hey, fashion road-kill,” he snarks back.

He’s the one who manages the finances (investments, included) of his single mom (Naomi Watts, Lieberher’s “St. Vincent” co-star). He’s tall and gangly enough to keep his bullied little brother (Jacob Tremblay) out of harm’s way.

But he can’t keep his cute neighbor (Maddie Ziegler) from the clutches of her creepy stepfather (Dean Norris). He can sense her trauma, see her bruises and guess what happens when the lights go out next door. And he can count the days she misses from school and is willing to cuss out the principal who refuses to act against the well-respected/well-connected Cavalry township police commissioner who is that evil stepdad.

So Henry, who delights in creating elaborate chain-reaction Rube Goldberg (Wiki him, too.) contraptions, makes plans to rescue her. It’s just that he gets these headaches and he might not be able to do the job himself. He needs to get his lonely, hard-drinking mom on board.

“Violence isn’t the worst thing in the world,” he reasons. “Apathy” is.

Director Colin Trevorrow, getting back to his “Safety Not Guaranteed” indie roots after a dip in “Jurassic World,” lets Lieberher have plenty of sweet, empathetic moments even as he’s plotting the crime that will free the neighbor girl he crushes on, the one with her hair always draped over one eye.

Watts, playing an overmatched, indulgent mom who never quite makes the “nature vs. nurture” argument for raising geniuses, gets to sing and play ukulele to her boys — one brilliant, the other also quite bright. Lee Pace makes an appearance as a sympathetic neuro-surgeon.

“Book of Henry’s” wild lurches in tone, from serio-comic and sweet to tragic and murderously violent, can almost be forgiven thanks to those grace notes, and the caper plot, which moves it right along.

But it’s just a bit off, from the child’s “solution” to this intractable problem Henry wants to solve, to the picture’s too-pat resolution. Trevorrow and screenwriter Gregg Hurwitz don’t let us know the girl next door. She’s just a remote object of pre-teen desire, sexualized in all the creepy ways Hollywood manages that.

The various manipulations and plot devices — the sobering reality of sickness, Henry’s omnipotent “narration” in his “book” and tape recorded instructions to his mother — don’t excuse the abrupt leap we’re expected to make, along with his mother, to Henry’s radical “solution” to the big problem he sees next door.

Like a beach book, we lean into the story, the more complicated and manipulative it gets. But like such books, we just shrug when we finally reach the end, knowing this everything-but-the-kitchen-sink melodrama will be long forgotten by summer’s end.

MPAA Rating: PG-13 for thematic elements and brief strong language

Cast: Naomi Watts, Jaeden Lieberher, Sarah Silverman, Dean Norris, Lee Pace

Credits:Directed by Colin Trevorrow, script by Gregg Hurwitz. A Focus release.

Running time:  1:45