The thrilling MMA conquest of a rookie genius fighter Wheesung, who was a promising sportsman with a natural sense of movement, quit exercising in high school due to an injury and lives a part-time life. In the meantime, he is invited to the match of MMA amateur Junghwan … He feels a strong thrill at the power of ‘Octagon’ that he encounters for the first time. 22-year-old Hwi-sung Lee, who was busy running away after giving up on everything. The moment he climbs into the Octagon, a spectacular flight that no one expected begins.