We find ourselves as the film begins, in a small suburban town that looks suspiciously like Chappaqua, New York, with leafy lawns, nice houses and friendly people. Very suspicious, very Hitchcock.

Here lives 11-year-old Henry Carpenter (an amazing Jaeden Lieberher) and his younger brother, Peter (the highly regarded, multi- nominated Jacob Tremblay of “Room”).

Older brother Henry is a sort of Rain Man with better social skills and a likability number in the high range.

Mom Susan, (Naomi Watts) works as a waitress in a coffee shop, hamburger joint. Naomi Watts as a high school graduate waitress? Yes, a girl has to work.

But Naomi is the best mom ever, a cheery barista who prefers to come home after serving chili dogs and beer, and relax by playing video games that her two boys are way beyond.

Our Henry is a no nonsense 40-year-old in a kid’s body, studious and sincere, well liked at school, and adept at keeping his kid brother from being bullied. Henry is probably the only 11-year-old who keeps the family checkbook clean and up to date.

Henry, probably when his dad died, started investing in the stock market, and checks his stocks daily. Mom lets him run the family economy, because he does it so well. He constantly has to remind her that the family needs a new car and updates on the house. Not until the end do we learn just how well Henry has done.

Henry is constantly watched by Christina, the girl in the next row in math class, (Maddie Ziegler) a sleepy eyed 11-year-old who lives next door to him. Christina has deep problems of her own, and Henry is aware of the situation. We’re moving now.

Christina’s parents are both dead, and she keeps to herself in the dark house she shares with her stepfather, Police Commissioner Glenn Sickleman (Dean Norris, “Breaking Bad”).

It’s not very long, after passages of exposition, that we learn that step daddy’s love for Christina has darkened and gone off the tracks. But he’s the Police Commissioner, who’s going to believe ill of him?

When Henry becomes aware of just how dark it is, and the difficulty of proving it, he starts a red covered book full of elaborate plans to eliminate the bad papa.

This is the point where “Book of Henry” departs from just another social problem movie of the week to a full blown teen thriller with chases, lots of dark woods, tree houses, a local mob connected gun shop owner and Henry’s elaborate plan with overlooked potholes that will produce unwanted collateral damage.

There is nothing a reviewer (there are none other than yours truly that will be provided until June 14th,) can reveal without giving away a huge, dramatic and heart-wrenching turn of events.

I leave you with that. Sorry.

The small cast includes SNL’s Bobby Moynihan as Naomi’s hash house boss, Lee Pace as a sympathetic doctor, and in a totally wasted and disconnected part, comic Sarah Silverman as Susan’s co-worker and comedy relief.

Colin Trevorrow (“Jurassic World” — 2015) directs as best he can with a script by Gregg Hurwitz that is full of more holes than a lace tablecloth. It’s the cast that saves the film, especially the incredible craftsmanship of boy stars Lieberher and Tremblay. Watts, always good, simply plows through with only a paragraph of good moments. But it’s Maddie Ziegler who stuns with a class show ballet number that sends a message.

Master cinematographer John Schwartzman (“Jurassic World, “The Amazing Spider-Man”) is given a lot of fun shots to play with and handles them well.

Nothing great here, but at least it’s not “Baywatch.”

J.P. Devine is a former stage and screen actor.