The heroes of the story are the boxtrolls in a small town.They not only steal children,but also steal food, which is a thorn in the town residents' side. But the truth is, the group of monsters have been raising an orphan named Eggs.The "modern family" formed from them in the underworld lives happily. But the town residents wanted to get rid of the boxtrolls. When Eggs grew up,he ventures into the ground to save his family, and manage to change the obstinate minds of the townspeople. As the movie posters said: heroes come in all shapes and sizes, even rectangles.