I/O

April 26, 2032, 12:12 AM, Tokyo. During the first lunar eclipse in three years, the Moon turns blood red, and strange, inexplicable events begin happening all over the city. Computers everywhere begin going haywire, students go missing, and and a boy receives a message from his sister who vanished more than two years prior. Nobody seems to know what is going on, and it seems like society is heading for a grand collapse...

I/O is a sci-fi mystery visual novel. There are three main protagonists: Hinata Aoi, a terminally-depressed teenage boy; Ishtar, a freelance programmer who leads the hacker team "Criminal"; and a mysterious man known only as "He". The player proceeds through one of four scenarios as their chosen characters, making regular decisions which will affect not only the flow of that scenario and lead to many different endings, but also affect what options are available in other scenarios, and even potentially unlocking completely new scenarios. Dialogue is fully-voiced, and there are quick-save and chat log options available.

The PC release, I/O revision II, adds additional character portraits and revises some of the text, but is otherwise identical to the original PS2 release.