Single mother Susan Carpenter (Naomi Watts) is raising her two young sons, Peter (Jacob Tremblay) and Henry (Jaeden Lieberher). Henry is a genius who takes care of the family's finances. When he suspects that his classmate Christina (Maddie Ziegler) is being abused by her stepfather, Glenn Sickleman (Dean Norris), he wants to expose the man, but because Sickleman is the town's police commissioner, he has to be careful.

With his mother's help, Henry puts a plan into motion that will gather information on what the man is doing, but because of Sickleman's position in the town, they run not only into skepticism, but put themselves at risk.

  Canadian Connection: Jacob Tremblay is Canadian.