 Dou asked Gao to safeguard their homebase, and then led 7,000 men against Guo, pretending to be betraying Gao and surrendering, particularly having Gao publicly execute a woman that Gao claimed to be Dou's wife.Guo, not suspecting Dou, proceeded at once to join Dou, planning to attack Gao together.Dou ambushed and killed him, seizing his army and horses.