Sensei has a friend and classmate, whom he refers to simply as K, who hails from the same home town and with whom he shared a common dormitory during his first years of study in Tokyo. K is the second son of a Buddhist priest but was sent to the family of a prominent local physician as an adoptive son. His adoptive family funds his study of medicine in Tokyo, but contrary to their wishes, K pursues his own passions of religion and philosophy. After his third year in Tokyo, he confesses his deception and is disowned as a result. Sensei feels some obligation to assist his friend, who is struggling to maintain an aggressive course of study while at the same time supporting himself. K views himself as an ascetic and strongly declines any form of financial assistance. Finally, Sensei convinces K to join him in his lodgings, arguing that K's presence there will serve toward his own spiritual betterment. After some persuasion on Sensei's part to win the widow's approval, K joins Sensei in the widow's home as a second boarder. After a while, with Sensei working behind the scenes, K warms to his new surroundings, emerges from his ascetic shell, and grows more sociable. Sensei is pleased with the improvement he's worked in his friend's demeanor but also begins to see K as a rival for the daughter's affection.