1) A boy named CJ falls down a slide in the park and breaks it, causing everyone to chase him. He falls into a deep, dark sewer where he has no food, water, light or warmth.
2) In the sewer, CJ sees a rope and considers climbing out but a ghost warns him of goblins above. Writing on the wall directs him to a house for help.
3) At the house, a goblin invites CJ to follow him out silently. They become friends and construction skeletons fix the broken sewer, preventing others from falling in. All the creatures become close friends in the end.