Richard Ranashinha de Vulpian, a charming British gem expert in Japan, is rescued by a noble student, Seigi Nakata, from rowdy troublemakers one night. Grateful, Richard appraises a sentimental pink sapphire ring for Seigi, leading to a partnership at his shop. Collaborating, they tackle unique gem tasks for clients, delving into the emotions and tales entwined with each precious stone.