By the end of the 20th century pollution became so heavy that the hole in the ozone layer expanded greatly, resulting in an acidic rain that rendered life on Earth next to impossible. Mankind had to colonize space, and began producing artificial humans (androids) to work in harsh conditions. As the danger was averted, however, the usage of androids gradually shifted towards mundane life. Female androids, known as "slave dolls", were used for sexual purposes until some of them rebelled and turned to crime. Special agents called "hunters" were dispatched to capture rogue slave dolls. Ryou Kanou is one of those hunters, and he is sent on a mission to apprehend an android named Reira. [From [url=http://www.mobygames.com/game/pc98/reira-slave-doll]Mobygames]