AI: The Somnium Files – nirvanA Initiative is a visual novel developed and published by Spike Chunsoft.

About

Six years ago, the right half of a corpse was discovered under mysterious circumstances. The left half was never found… until six years later, when it was discovered completely fresh with no signs of decay, as though the victim was alive until just recently. Now, newly-appointed Special Agent Mizuki and her AI partner Aiba are tasked to solve the bizarre Half Body serial killings…