"Now's the time for monsters to make friends with humans," says Bevil's father "We must be helpful to them, and do good things." The concept appeals to the boy. He will go down to earth, find a human, and do good things.
But the problem is, Bevil doesn't really know what "good things" are. Bevil is in fact a cute baby devil who is rather naive. When he meets 10-year-old Ryota, and moves in with the boy's family, Bevil tries his best--but almost always fails. And Angela, his mischievous rival, constantly trips him up.

"Maybe we need more Wonder Monsters," thinks Bevil. With a shake of his magic hammer, a clutch of cute and cuddly monsters pops out. "Will these Wonder Monsters do good things?" he wonders.

[Source: NHK ENTERPRISES]