In defiance of the prohibition against human presence, a young witch named Nicola ventures into the realm of demons. There, she crosses paths with Simon, a demon merchant, who opts to accompany her on his travels despite their differing origins. As their unlikely friendship flourishes, the duo embarks on a series of thrilling escapades across the demon world, encountering enchanting locales, forming bonds, and braving occasional dangers. Amidst their adventures, Nicola revels in the discovery of her own magical abilities, finding delight in unraveling the mysteries of this wondrous dimension.