It’s rare that movies in this series result in me actually saying, “I can’t believe I just watched that.” “Divergent” certainly made me say that, as did the end credits of “Catch Hell.” But as I was walking to my car after seeing “The Book of Henry,” I actually said, “I can’t believe I just watched that.”

The plot of “The Book of Henry” is an utterly bonkers idea that I can’t believe a bunch of a-list people signed on to do this movie both in front of and behind the camera. I also am a little surprised this has a distribution company as major as Focus Features would distribute this, but then I remember “Collateral Beauty” exists. As I texted a friend after this movie, this a movie where almost every narrative decision is a hard left turn. And because of that, I’m going to let you know I am going to spoil this movie because I can’t talk about the insanity of this plot without spoiling it.

Henry (Jaeden Lieberher) is a 12-year-old wünderkind who is an investment genius, an inventor, a co-parent, and apparently went to medical school. In fact, in a movie that largely does not know how children behave–except in a moment with a great joke in the cafeteria late in the film–the only way we can excuse Henry’s stand-up philosophy in his fifth grade class is the fact that we are shown he’s such a genius, he can beat out the girl in “Gifted.” Henry largely takes care of his waitress mother, Susan (Naomi Watts), and his brother, Peter (Jacob Tremblay). He even has a crush on the girl next door, Christina (Maddie Ziegler).

The movie has a distinct feel in the first 15 minutes of being a heartwarming film for the whole family, which would explain the fact I was the only person who went to the theater alone. Michael Giacchino even has a nice peppy score for the opening scenes as we see the idyllic small upstate New York town the characters live in.

But then we get to the first hard left turn, where the movie momentarily turns into an after school special on child abuse. Henry suspects Christina is being abused by her stepfather, Glenn (Dean Norris), but he seems to be the only person who cares. After the school principal (an underutilized Tonya Pinkins) explains to Henry she can’t do much because Glenn is the police commissioner, he decides to take it upon himself to figure out how to kill the police commissioner.

At that first twist, I wasn’t too surprised because that’s what I knew from the reviews on the internet. In fact, the general word about this movie was that it’s the movie about the boy genius who decides to kill the head of the police. And yet, that’s not the craziest thing about this movie. While Henry is in the process of his plot, he has a seizure and is diagnosed with a brain tumor by a doctor (Lee Pace), who is left speechless as Henry rambles off everything he can assume about the tumor. The movie then has the cojones to kill off its title character halfway through the movie. While this is such a stunning move, the big question is how the movie can sustain itself for the rest of the run time. In the midst of their grieving, Peter finds his brother’s notebook. From there, his mother is coached through her oldest son’s notes into killing Glenn.

That’s right. This is a movie in which a 12-year-old boy genius dies from a brain tumor and then, from beyond the grave, coaches his mother into killing the police commissioner, who is abusing his stepdaughter.

The movie really doesn’t become interesting until it gets to the point where we realize what the movie is becoming. In fact, you spend a majority of the movie up until Henry’s death wondering if we’re supposed to root for him. He is presented as such a smug asshole, you don’t know why every fawns over him. Then he starts plotting in intricate detail how to kill his neighbor and you actually hope he gets caught, that someone pauses and wonders what is going on with this beloved boy genius. And quite frankly, it’s a little slow up until the point where the script actually makes the decision to kill him off–with the tone, I was actually expecting for a miraculous recovery–and turn the movie into, “Hey, I’m going to have my grieving mother kill an abuser.”

The movie, which is written by crime novelist Gregg Hurwitz, feels more like it was written by a robot than someone who actually lives among people. If we explain Henry away as being a sociopath–or even being raised to be cold, like the Holmes family in the Charlotte Holmes novels–his behavior actually makes sense. Susan is portrayed as a doting mother who also wants to be cool, a woman who can barely get herself dressed most days, and a woman who feels lost while she’s raising this genius. I actually thought from the beginning of the movie this was going to be a poor man’s “20th Century Women,” which is actually an insult to “20th Century Women.” Peter is one-note and the rest of the characters feel so poorly fleshed out. Sheila (Sarah Silverman) is Susan’s co-worker that might be an alcoholic, but the movie is done with that character development as soon as it introduces it. Pace’s doctor keeps showing up for reasons that don’t really make sense and it is just explained away that he’s checking up on the family. Even Christina, who should arguably be one of the characters you care the most about, is reduced to an empty vessel that keeps insisting she’s fine. Like many of the films in this series, it creates characters just to fill up the screen, which is a major problem in a movie that should have a lot of emotional heft.

The script also has handles child abuse in a very clumsy manner. At one point, Henry comes bursting into the principal’s office and begins listing off the signs of child abuse. Child abuse in this film is treated as little more than a list of warning signs, including a moment where Peter offers Christina a cupcake when she’s not eating in the cafeteria and she says, “No.” While the movie does end up with the big murder plot entangling Susan, the child abuse is really just a moment for Henry to save the day. Much like how rape is often treated in storytelling, the child abuse in this movie is of more narrative importance for Henry than the actual victim. The closest we come to seeing any of the real emotional trauma she’s experiencing is when she’s dancing at the talent show, but I’ve also seen enough art and dance performances to know that most good performers emotionally connect to what they’re doing.

The worst part about this movie is it’s a very well-cast in what is ultimately a very competently made movie. Everyone involved here is just saddled with such a rotten script it ends up becoming a bad movie. There’s certainly something that could be salvaged from this movie. There could be a movie solely about a boy genius who tries to win the heart of the girl he has a crush on. You could have a movie about a single mother who, with the help of her two overly precocious children, helps her co-worker overcome alcoholism. You could have a movie about a mother grieving the loss of her oldest son who is pushed towards dating the neurologist who treated her late child, which would actually help answer the question of “Why does Lee Pace keep showing up?” You could even start the movie at Henry’s seizure and death and go with his mother discovering his notes and learning about his plot and her trying to deal with all of those details. Any of those would be better than this baffling mess of a script that led to us possibly having the biggest “What on earth did I just see?” of 2017.