In the underworld known as Felicidad, humans and monsters live in harmony. The farmers who breed and command these monsters are known as Farmagia. Thanks to the Farmagia, the Magus Diluculum, and the Magus's generals, the Oración Seis, the society of Felicidad has flourished, until the fateful day when the Magus dies. On that day, Glaza, one of the generals of the Oración, seizes the opportunity to take power for himself.

As Glaza and his army march into the city of Centvelt, a resident Farmagia named Ten attempts to stop them. Although he initially fails, Ten inspires others to stand up against the despot. With the help of a general from the Oración who turns against Glaza's mad quest for power, Ten and his friends must work together with their monsters to prevent the further subjugation of Felicidad.