The player takes the role of Rance, a young guy who works in a private investigator's office. One day, the boss has a new assignment. A girl named Hikari, a student in Paris High School, has been missing for several days. The player's job is to find the girl and to report whatever mysterious circumstances the player might encounter during the investigation.

Rance: Hikari o Motomete is a role-playing game with hentai (erotic) elements. The game is viewed from first person perspective and is controlled via a menu. The player may navigate the character in the city by choosing directions ("go north", etc.), examining locations and entering buildings. Outside, the player also battles monsters. Battles are turn-based and monsters appear on the same screen the player see before engaging in combat. The player can equip weapons and armor, use items, and gain experience points from combat.