Slippery creep in the flush tank, a hairy beast resembling the monster from The Scarlet Flower, giant woodlice under the bed — all of them actually exist. All they need is to scare children, because they get electricity from children's screams. The feature-length animated film tells about crises in the world of monsters, their lives. But one day the peaceful life of the monsters is under threat: a child enters their world. And there are so many troubles with children that they can drive even the monsters crazy.