While Cao Cao was away in Xu Province, his subordinates Zhang Miao and Chen Gong rebelled in Yan Province and defected to another warlord Lü Bu. At that time, Cao Cao's family members were in Juancheng County, so Xiahou Dun led a lightly armed force towards Juancheng to fetch them. He encountered Lü Bu's army on the way and engaged the enemy in battle. Lü Bu withdrew his forces and took advantage of Xiahou Dun's absence to conquer Puyang and capture much of Xiahou's supplies and equipment. Lü Bu later sent his men to pretend to surrender to Xiahou Dun, who fell for the ruse and was taken hostage by the enemy in his own camp. Lü Bu's men demanded a heavy ransom. Xiahou Dun's troops became fearful and confused when they heard that their commander had been taken hostage.