Second-year Kasaba University student Nakata Seigi rescues a foreigner being harassed by drunks. Wavy blond hair, blue eyes, and clear skin. The man who speaks unfaltering Japanese is Richard, a very competent jeweler with customers both domestic and international. Thanked by Richard for being a "hero of justice," Seigi hires Richard to valuate a memento from his late grandmother, a pink sapphire ring. Through Richard, the mystery hidden in the ring is eventually revealed...

Seigi begins working at "Jewelry Etranger." Richard tells him "you will exhibit no prejudice, nor speak in a discriminatory manner," but fails to understand his intention. One day, Akashi Mami comes to get a ruby valuated with the strange request to determine if the gemstone has been heated or not. Mami's brooding expression reminds Seigi of his grandmother, and he is curious. Meanwhile, Mami's troubled fiancee Homura Takashi arrives at the store...

A small customer arrives at Etranger: second-year grade school student Kasaka Hajime. Hajime asks for a gemstone like the one he has and pulls an unset Cat's Eye out of his bag. Seigi is surprised and attempts to question Hajime about his situation, but Hajime obstinately refuses to speak to Seigi, who treats him like a child. Meanwhile, Hajime slowly begins to open his heart to Richard, who treats him like a customer...

Yamamoto arrives looking for a garnet for her engagement ring. Seigi feels positively about Yamamoto who has chosen a garnet rather than the standard diamond. However, when Yamamoto returns to the store, she seems to provoke Richard by stating that beauty is an advantage. Richard goes on to gently unravel the feeling sealed deep inside Yamamoto's heart...

One day, Seigi runs into Hase Keigo, the senior from his karate class who he admired. Delighted by their reunion, Seigi refers Hase to Etranger since he is looking for a jeweler. Meanwhile, Richard is concerned with Seigi's over-exuberant desire to help his senior. Hase arrives at Etranger looking to sell a fire opal. He begins telling the story of Seigi's grandmother as though it is his own...

Seigi's university friend Shimomura introduces him to Okita Ayumi, another member of his club. Ayumi has been looking for clues concerning her missing boyfriend. When she visits Entranger, she presents her only lead: a turquoise earring. Because her boyfriend went missing immediately after giving her the earring, she's searching for the store that sold it. However, when Richard sees the earring, he behaves differently than normal. Seigi becomes curious about what's going on inside Richard's head.

A number of gemstones known as the Azuma Collection are being put up for auction. The manager of the Ito Shobin Company hires Richard and Seigi to win a gemstone called the Buddha's Hand Citron. During the pre-action preview, Seigi meets an acquaintance of Richard's named Shin. It would seem that he is also attempting to buy the Buddha's Hand Citron, but how will the auction end...?

When Seigi learns that his college classmate Tanimoto Shoko is going to a marriage meeting, Seigi is disheartened. Seigi has some feelings for the gemstone-loving Shoko. All he has left in his possession is a teardrop-shaped loose aquamarine he purchased from Richard that he intended to give to her. Unable to say anything to Shoko, the discouraged Seigi returns to Etranger, where Richard gently encourages him by telling him to live without regrets. However, behind his words is a part of Richard's past unknown to Seigi...

One month has passed since Richard`s disappearance, and it`s now autumn. Seigi asks Richard`s mentor Saul who has appeared at Etranger about his whereabouts, and in return Seigi is asked why he wants to see Richard. However, Seigi searches his own feelings and decides what he will do when he sees Richard and heads to London alone. On the way there, he meets a man named Jeffrey claiming to be a relative of Richard`s... Source: crunchyroll

Working off of the hint Richard left for him, Seigi heads to the lapis lazuli exhibit at the British Museum. There he finds Richard disguised as a woman. While carefully watching their surroundings, Seigi and Richard flee from the scene. Richard attempts to send Seigi back to Japan, but Seigi refuses to leave until they talk, and the two disagree. When the past Richard had kept secret is revealed, how will they choose to act-- Source: crunchyroll

One winter day after Seigi and Richard have returned to their normal lives, Seigi helps an elderly woman named Chieko carry her bags. He is served pudding at her house as thanks, where he finds a photo taken in England and a copy of Les Miserables. Seigi recalls the governess Richard described to him and asks Chieko about it, but Chieko`s expression is dark... Source: crunchyroll

Seigi`s father Shimeno Hisashi appears before him. Shimeno divorced Hiromi when Seigi was in grade school and has approached him now that he`s grown. Though Seigi drives him off, Shimeno begins appearing everywhere Seigi goes. Not wanting to cause trouble for Richard or anyone else around him, Seigi tells Richard he wants to quit working at Etranger while hiding the reason from him... Source: crunchyroll