Killer Ape summary: Warfare evolved in the far-off years, with AI technology rendering human soldiers obsolete. Suddenly, in the 22nd century's twilight, an enigmatic vessel christened "Gayla" crippled all AI, prompting humanity to rediscover the art of combat. Seeking to enlist as a soldier, Teppei Sakamoto joins the armed forces and is thrust into a simulated Battle of Waterloo to hone his killing prowess.