After saving a mysterious drug trafficker known as K, surgeon Gu Nian is dragged into the brutal world of a drug cartel. Forced to bargain with the elusive K, she finds herself drawn to him amidst perilous encounters. To protect her, K sacrifices himself in a fatal confrontation with the drug lord Peng Li, vanishing without a trace. Half a year later, Gu Nian meets Song Qian, K's mirror image, now a cold corporate executive with a fiancée. He denies everything. Heartbroken, Gu Nian leaves. Yet when her pursuit of her mom's killer puts her in the crosshairs, the hostile Song Qian repeatedly saves her, forcing her to uncover his true identity.