Earth and Sky is an interactive fiction trilogy written and produced by American author Paul O'Brian about the adventures of a brother and sister who gain superpowers while searching for their lost parents.
Adopting the superhero names 'Earth' and 'Sky', the siblings decide to search for their parents themselves and defend the campus from an accidentally mutated monster.
The story file can be downloaded for free online and though O'Brian recommended using Frotz, Earth and Sky is compatible with several interpreter programs which are available as freeware.
[1] The game received mixed reviews; it was commended for having entertaining, humorous and descriptive narratives but also criticized for its short length and use of a menu system in dialogue.
[10] Luminous Horizon placed first in the 10th Interactive Fiction Competition in 2004 and was nominated for Best Individual PC and Best NPCs in the 2004 XYZZY Awards.