Richard’s cousin, Jeffrey , plays a significant role as an antagonist/foil, representing the cold, duty-bound side of the family.

This time, the "client" is Seigi himself. The jewel in question isn't a sapphire or a diamond, but the fractured memories of his own family. The volume opens quietly, with Seigi receiving a letter from his estranged mother—a woman who abandoned him and his father years ago. Enclosed is a modest aquamarine ring, with a request: "Sell this. I need the money."

The central motif of this volume is the desire for stasis.

True to the series, Volume 9 continues to use gemstones as a mirror for the human soul. While previous volumes focused on episodic jewelry-related mysteries, this installment leans heavily into the and the deepening bond between the two leads as they navigate external political unrest and internal emotional revelations. The Case Files of Jeweler Richard (Light Novel) Vol. 9