What would you do if you were suddenly forced to transfer to your rival school, just because you got caught up in someone else's fight? When Lee Ha-eun is sent to the notorious Ganghak High, she never expects to cross paths with Geum Seong-je, a violent, unpredictable fighter with a three-second rule for anyone who dares to meet his eyes. As Ha-eun struggles with bullying and isolation, she finds an unexpected protector in the very boy everyone fears. Because in a world ruled by fists and fear, three seconds is all it takes to fight, to fall, or to feel something real.