Gaston Bonaparte, a young Frenchman, visits Tokyo to stay with his pen-pal Takamori. His appearance is a bitter disappointment to his new friends and his behavior causes them acute embarrassment. He is a trusting person with a simple love for others, and he continues to trust even after they have demonstrated deceit and betrayal. He spends his time not sightseeing but making friends with street children, stray dogs, prostitutes, and gangsters. This novel charts his misadventures with sharp irony, satire, and objectivity.