During the Song dynasty, after the upright prefect Bao Zheng executed Pang Yu for embezzlement, the grand tutor Pang Ji sent assassins to avenge his son's death. A chivalrous man, Zhan Zhao the "Southern Hero", saved Bao and was conferred the title "King Cat" by the emperor. This title invoked the jealousy and anger of Bai Yutang the "Brocade-Coated Rat" - as rats were considered cat food - who went to the capital Kaifeng (also known as Bianjing) to challenge Zhan.