As earthquakes occurred in the kingdom of Itchy, and demons began roaming freely through the wilderness, the king realized that an ancient prophecy is about to be fulfilled, and the entire world is in danger. The valiant swordsman Soleil lives in the capital city, and the king entrusts him with the task of protecting the two Moon goddesses, and retrieving the Sun Sword, which are necessarily to prevent a magician known as Silver to use the Gears of Fate for his evil purposes...

Sol Moonarge is a traditional Japanese-style RPG. As in most games of this genre, the player navigates the main hero and his companions on the top-down "world map", entering towns to buy weapons, armor, and items, as well as hostile locations which are necessary to complete to advance the plot in a linear fashion. Enemy encounters are random; combat is turn-based and viewed from first-person perspective.

As in most Japanese RPGs, the characters level up automatically, after having accumulated a set amount of experience points; specific weapon and magic proficiencies, however, grow depending on the amount of times player-controlled characters use that particular type of weapon or spell.

There is a day-night cycle (on the world map only), which influences people's schedules: at night the shops are closed, but certain characters might appear only during that time.