ON THE AFTERNOON OF 15 JUNE 2020, several dozen Chinese and Indian soldiers stared each other down on a desolate Himalayan mountainside, more than 4,000 metres above sea level. Over the past four decades, such standoffs have been common along the ‘Line of Actual Control’ in the disputed Sino-Indian borderlands, particularly during spring and early summer. This is when both sides resume patrolling and consolidating their positions after the winter freeze. Sometimes standoffs have resulted in fistfights or stone throwing, but no personnel of either side had died on the border since 1975, when four Indian soldiers were shot and killed on a patrol at Tulung La, a pass in Arunachal Pradesh at the far eastern end of the disputed border. What happened next on that day in June remains shrouded in mystery and recrimination. This incident sparked one of China’s most dangerous foreign policy crises in 2020. What happened in the Himalayas? How did the confrontation begin, and why did it escalate? And what role has Indian nationalist outrage played in its handling?