[1] The Day Boy and the Night Girl begins by telling of a witch named Watho who, in her pursuit of complete knowledge, undertook an experiment to mould two people from birth by strictly controlling their environments.
Watho desired the opposite for the girl Nycteris, who knew no other world than the stony chambers she had been born in and no other light than that provided by the single dim lamp.
Nycteris was filled with wonder at this glorious new light and the rest of nature; she returned to her rooms before daybreak, desiring to see the outdoors again and not wanting to spoil her chance by arousing Watho's suspicions.
Photogen regained his courage immediately; assuring Nycteris that there was now nothing to fear, he went on his way, despite her terrified pleas that he stay and protect her from the blinding light.
Photogen, wishing to prove his courage and driven by guilt on how he left Nycteris, stayed up for other nights, only to experience similar results.
Nycteris convinced a weakening Photogen to not waste time, make peace with the night as she did with the day, and run away immediately, guiding him in avoiding any dangerous or scary animals thanks to her strong sense of smell and hearing.
Grateful for ending her terror, Watho's servants helped Photogen and Nycteris head to the king and queen to tell their tale.
Watho attempts to gather and subjugate, Photogen tries to conquer through ability, and Nycteris uses her imagination to further her understanding and knowledge of the world to better see how she fits in it.