It is a semi-real-time adventure game developed in 1983. It was released by MIA under the title “ONION HOUSE”, although it was originally known during development as “Circumference.” The game features a distinctive system that combines the command-based adventure game format popular at the time with real-time action elements. It is characterized by a high level of difficulty and complex puzzles, and has been regarded as a title that divided opinions since its release. The game was distributed on cassette tape. Its original retail price was 980 yen. The supported platform is the PC-6001.

The story centers on the theft of the legendary diamond from Onion Planet, said to be the largest diamond in the world. The jewel has been stolen by the mysterious Phantom Thief Onion, and despite an extensive search by the authorities, its whereabouts remain unknown. Eventually, it is discovered that the thief has hidden the diamond inside the power room of an abandoned factory. The facility has been left unused for a long time and is partially damaged, and to make matters worse, it is now occupied by aliens. High-voltage electricity is still flowing through the walls, making the location extremely dangerous. The player’s mission is to infiltrate the factory, locate the diamond, and escape as quickly as possible. To assist in this task, the player is accompanied by Papicon, a support computer that helps search for the diamond. However, Papicon requires electrical power to operate, which places a strict time limit on the mission. The game begins in one of the factory’s rooms. While Papicon can scan and display information about the immediate surroundings using short-range sensors, its limited memory prevents it from providing detailed information about areas beyond that.