The book takes place in the city of Monstropolis, which is home to many monsters of all shapes and sizes. Two monster friends work for the largest “scare” corporation - “Monsters Inc”, in the positions of “senior children’s scarer” and “assistant scarecrow”. For monsters, the screams of children are a source of energy necessary for life, and the employees of this corporation are engaged in the “extraction” of this valuable “resource.” The problem is that, according to monsters, children are toxic creatures for them, and therefore any contact with them is prohibited. The situation changes when one of the victims, a little girl, accidentally ends up with the monsters in their world, jeopardizing both the heroes’ careers and, possibly, their lives.