“先生”在大学时代为了照顾朋友K将其带到自己的寄宿家庭中去。不料同朋友K一同爱上房东漂亮的独生女儿。“先生”设计使K自杀，自己如愿以偿。但婚后一生都遭受良心和道义的谴责。

另一种猜测是寄宿家庭中的“小姐”与“夫人（小姐的母亲）”共同设计使K自杀，从而刺激“先生”与小姐结婚。

故事的亮点就在于令旁观者无法探知其中的真相。

A young man lives in Tokyo as a renter with a widow and her daughter. He invites his childhood friend, a monk, to come live with him, hoping to help him. When the monk falls in love with the widow's daughter, it drives a rift between them. The story is narrated from two points of view, the man's and the monk's.