Lee Jae-ha has lived his entire life avoiding fights. With no particular dreams or talents, Jae-ha suddenly realizes he possesses an incredible natural talent for martial arts. Thinking, 'What's the use of being good at fighting...', he shows no interest despite his friend Lim Myung-in's persistent encouragement to try mixed martial arts. Without Jae-ha knowing, Myung-in secretly applies him to 'Never Back Down', a reality program that searches for hidden rough diamonds in martial arts...