In an imaginary world, the first Guardians made a small Sun and Moon to warm up a small planet where many types of people live. For generations, the Guardians preserved the harmony of the world, with the people of the day and night living in relative harmony despite being different from each other. However, in the Underworld deep within the planet, Necross, a failed and corrupted Guardian of the Sun who tried to steal the Sun for himself out of envy, only for the warrior Xolal to banish him, awaits the opportunity to plunge the world into darkness.