Akiho Takeda is assigned to #3 investigation team for The Tokyo Metropolitan Police Department. On her first day at work, a burglary takes place at a jewelry store in Shibuya. The case though is taken by the #1 investigation team which Akiho hoped to join. Nevertheless, Akiho goes secretly to the jewelry store where the theft took place. Later, a safe at a jewelry store in Roppongi is broken into. Stolen from the safe is the diamond called "Besu". The "Besu" is one of three diamonds that makes up the "Kuraida Family's Three Sisters". The other two diamonds are "Ani" and "Kyasari". The diamond "Ani" was stolen from the jewelry store in Shibuya, that occurred a few days earlier. Several people believe the two diamond thefts were done by the same person(s), but Akiho mentions the techniques used by thieves are different. Yet, Akiho believes there must be a connection between the two cases.
