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