The story begins with the protagonist, a Chinese student in San Francisco, writing to his friend Chong Fu Sin in Hong Kong. He recounts an encounter with Fong Li, who hurriedly left a tong battle, claiming he had a date. This sets a humorous tone for the letter.

In class, the students engage in a lively discussion. The professor asks Ah Su to define "velocity." Ah Su, thinking of a velocipede, gives an incorrect definition, leading to the protagonist offering a humorous definition involving a man letting go of a hornet. This exchange exemplifies the language barriers and cultural differences among the students.

The conversation then shifts to Asia. The professor idealistically speaks about the unity of Asian people in pursuit of knowledge. This prompts Ah Su, Abdul Hamid, and Gungra Lal to discuss the greatness of Asia, which quickly devolves into a heated argument about religious and ethnic superiority. Ah Su suggests Asia would improve by expelling all Mohammedans, prompting a hostile exchange between Abdul Hamid and Gungra Lal, nearly resulting in physical conflict.

Kato Kimura and Galuk Noyon also join the fray, each defending their ethnic groups and criticizing others. The class further fragments into smaller arguments, with students defending their respective heritages and engaging in nationalistic bravado.

The classroom descends into chaos as students start physically fighting. Kato Kimura wrestles Galuk Noyon with jiu-jitsu, Abdul Hamid and Gungra Lal grapple, and Abdullah Khan attempts to use a Khyber knife against Rinjii Singh, who retaliates with a table. Ali Massar indiscriminately swings a Malay kris-knife at everyone, adding to the mayhem. The professor, overwhelmed and cursing, struggles to maintain order.

Eventually, the protagonist and several other students flee the scene. Despite the chaos, all students return to the next class. The professor, however, makes a bitter remark about the futility of trying to instill brotherly regard among "heathens," suggesting some students should return to Asia.