I’ve got a pretty high tolerance for movies, even syrupy ones, about super-gifted kids and am generally willing to give them some leeway as metaphor or fairy tale.  So I’m okay with “August Rush,” “Pay it Forward,” “A Monster Calls,” etc.  But “The Book of Henry” crosses the line from syrupy to smarmy, and where it wanted to be endearing, it was annoying, and then infuriating.

Jaeden Lieberher, who is making a career out of playing preternaturally wise and powerful children, has the title role as Henry, an 11-year old who is the kind of genius only found in movies. Not only is he a total braniac who understands architecture, finance, electronics, existential conundrums, weapons, and engineering, he has a rapier wit and knows the difference between different kinds of tumors and can read an MRI. Furthermore, he is a near-empath who instantly understands the people he cares about. In other words, he is not a character; he is a symbol and his purpose in the story is to give other characters important life lessons.

Henry has a younger brother, Pete (Jacob Tremblay of “Room”), who is in the movie to play the role of Normal Kid. And they have a mother, Susan (Naomi Watts), who is loving and devoted but irresponsible. Henry is the grown-up in the family, stopping at a phone booth after school to place complicated brokerage orders.

Let’s pause for a moment on that last point. Yes, I said phone booth. Even though the movie takes place sort of now (there are cell phones, a coffeemaker, video games, and a super-duper weapon), it has a deliberately retro feel. Henry and Pete use old walkie-talkies, barely a glimpse of a laptop (who needs one; Henry’s a walking Wikipedia). Susan is a waitress at a diner that could be out of the 1950’s, though her boss (“SNL’s” Bobby Moynihan) offers to pay her by direct deposit. You do not need to be Henry to figure out that this is supposed to lull us into cutesy-ness.

Henry has a crush on the girl next door, a classmate named Christina (Sia muse Maddie Ziegler), who lives with her stepfather, Glenn (Dean Norris), the town’s police commissioner. Henry senses that Glenn is abusing Christina. When Glenn’s position of power makes it impossible to protect her through official channels, he comes up with a dangerous plan to keep her safe.

To say more would be to risk spoilers, so I will just note that pretty much everything that happens after that is intended to be touching and poignant but  none of it is .   Lee Pace does his best with the thankless role of Doctor Perfect, who would make Prince Charming look like the guy who gets eliminated in the first episode of “The Bachelorette.” And Sarah Silverman adds some sass as Susan’s best pal, who joins her in wisecracks about how they aren’t rich and in getting drunk.  Christina has a lovely dance number in the school talent show.  And Watts is marvelous as always.  But the story’s preposterousness and manipulation thwarts their best efforts to provide some grounding.

Parents should know that the movie’s themes include child sexual abuse, attempted vigilante murder, and a very sad death of a child, and suicide. There is some strong language, a drug reference, and drinking and drunkenness.

Family discussion: What should Susan have done about the couple in the store? What made Susan change her mind?

If you like this, try: “Phenomenon” and “Disturbia”