The Case Files of Jeweler Richard Novel Volume 10 was written by Nanako Tsujimura with illustrations by Utako Yukihiro.

Octavia, the wealthy young lady who has stymied Richard at every turn, invites Richard and Seigi to a hotel in Nuwara Eliya, a city that boasts the finest mountain resorts in all Sri Lanka. The duo will need help from every ally they can summon, including Jeffrey and Henry, to thwart Octavia's schemes - but what exactly is the young mastermind planning? And what does this mean for Richard and Seigi's relationship?