In Chapter 100, Sima Yi warns Cao Zhen that Shu forces will, within the next ten days, launch an attack on Mount Qi (祁山; the mountainous regions around present-day Li County, Gansu), a strategic location which would allow further incursions into the Wei heartland. After Cao Zhen refuses to believe Sima Yi, the two make a bet and each of them leads half of the Wei army to guard the valleys to the east and west of Mount Qi. Cao Zhen prepares for battle halfheartedly as he thinks that he is right. Seven days later, when his scouts report that a small number of Shu soldiers are approaching the valley, Cao Zhen sends his subordinate Qin Liang (秦良) to lead 5,000 men to survey the terrain. As Qin Liang and his men travel deeper into the valley, they fall into an ambush by Shu forces led by Liao Hua and Guan Xing and are completely destroyed. The Shu forces then disguise themselves by wearing the Wei soldiers' armour and uniform and infiltrate Cao Zhen's camp. In the meantime, Sima Yi encounters and defeats Shu forces led by Wei Yan. When he learns that no enemy forces have been spotted at Cao Zhen's side, he immediately leads his troops to Cao Zhen's camp. By then, the Shu infiltrators have launched a surprise attack within Cao Zhen's camp. Sima Yi shows up in time, drives back the Shu forces, and saves Cao Zhen. Cao Zhen feels so ashamed of himself that he falls sick. Zhuge Liang writes a letter to Cao Zhen to taunt and insult him. Cao Zhen becomes so angry after reading the letter that he coughs blood and dies that night in his camp. Sima Yi sends his dead body back to Luoyang, where he receives a proper burial.