On her engagement night, the heroine, to fulfill a promise to her unwell brother, unexpectedly shares a room with Lou Jingyang. But a mistake leads to her waking up in the arms of Lou Jingyang’s dangerous and notorious second brother, Lou Xiao—the ruthless, rebellious “mad dog” of Yun City. Lou Xiao is known for his brutal tactics and disdain for rules, and he forces the heroine to witness her fiancé’s infidelity. To save face with her family, she reluctantly agrees to have a relationship with Lou Xiao, inadvertently tying herself to him. When Lou Xiao blackmails her with their secret, she realizes his dangerous nature and tries to distance herself. But after saving him from an assassination attempt, Lou Xiao softens and decides to repay the heroine’s kindness. However, when her fiancé, Lou Jingyang, pressures her into stealing documents from Lou Xiao, she finds herself caught between both brothers. Lou Xiao, furious at her desire to sever ties, threatens to expose their past.