In a dystopian world ruled by pharmaceutical companies, an orphan named Beck sets off to find her missing mentor following the only lead she has: unlicensed cage fights! Fifteen years after a global civil war brought on by health, economic, and ecological crises, the world has settled into tenuous peace under a regimented civilization. The majority of the populace lives in large, sprawling urban centers under strict military and medical surveillance. The remainder lives in smaller rural areas, resisting the rigidity of the cities. A stranger to both worlds, a young girl named Beck has entered the rural town of Bajara in search of her missing mentor, Kal. The trail leads her to a free-fighting ring known as The Cage and a fight organizer named Mr. Eddy. Now, she finds herself fighting her way to the answers she seeks, each victory a step closer to Kal. But there's something special about Beck, and it's grabbed the attention of local officials, as well as the underground fighters! From French mangaka Mathieu Reynes comes The Theory of K.O., a hard-hitting, high-kicking, faster-than-lightning story that's sure to be right at home on the bookshelf of any shonen manga fan.