One night, Masayoshi Nakata, a college student with a strong sense of justice, rescues a beautiful foreigner, Richard, who was entangled with a drunk. Knowing that he is a jeweler, Masayoshi asks him to identify a ring that his grandmother had hidden until her death, a ring with a story behind it. Richard's examination reveals her past, the truth, and her feelings. This leads Masayoshi to work part-time at "Jewelry Etranger," a jewelry store in Ginza owned by Richard. The relationship between Richard and Masayoshi changes little by little as they unravel the various "mysteries" that are brought to Etranger on a daily basis. However, both of them have their own secrets that they will not reveal to anyone.