Chaos;Head, stylized as ChäoS;HEAd, is a Japanese visual novel developed by 5pb. and Nitroplus. It is the first game in the Science Adventure series and is described by the development team as a "Delusional Science NVL". The game's premise revolves around a high school student named Takumi Nishijo who unknowingly walks into the scene of a gruesome murder on his way home. More mysterious events start happening afterwards as more gruesome murders occur in the area. Takumi struggles to cope with reality and the delusions he experiences as he tries to avoid getting caught by the perpetrator behind the chain of murders.