Scooby-Doo and Shaggy must go into the underworld ruled by The Goblin King in order to stop a mortal named The Amazing Krudsky who wants power and is a threat to their pals: Fred, Velma, and Daphne.

Eulogio Soto lives with his mother. To please her, he tries to locate her brother because she will have to undergo a delicate eye operation and he fears that he will never be able to see her face again. The youngest son, who does not know who his real family is, lives in a luxurious mansion. In the search for his lost brother, Eulogio will be "found" by a woman who, like a goblin, makes life impossible for him to help him by all means.

The film tells the story of a girl who arrives in the city with her young son and must take care of an old house where an elf lives. One day the child disappears mysteriously, which will motivate his mother to do the impossible to recover it.