Nocturnal Illusion is a Japanese bishōjo eroge, developed by Excellents Japan. It was translated into English and released in the United States in 1997. JAST USA later acquired the rights to re-release the game after the original localization company (RCY Brothers) had gone under. In 1998, a 2-CD revised version of the game with better graphics, sounds and this time with characters voices was released in Japan, by Apricot. It was never translated. The game served as inspiration for an amateur adventure game 5 Days a Stranger.