Hideki Sato, heir to a family-run chemical industries company, is abducted, and the ransom is the “Tear of Florence”, a diamond long thought to be lost. Yet the current president of the company, Zenichiro Sato—Hideki’s father—refuses to give into the demand, willing to sacrifice his own son’s life.Zenichiro’s secretary, Goh Makiba, is stunned. In fact, he is the one who has kidnapped Hideki in an attempt to regain the “Tear of Florence”, which he knows was behind an incident 25 years ago in which his mother was driven to suicide, sacrificed for the sake of this very company.As the deadline for the ransom nears, Zenichiro collapses from a relapse of his ailment. Zenichiro’s younger brother and the company’s vice president, Yujiro, sees an opportunity to take over control of the company and begins orchestrating a coup.Goh’s accomplice, Kei—a co-worker at the company—grows concerned that Goh is about to become a murderer. When she visits Sanae Makiba, the woman who raised Goh, she learns a surprising truth about what happened 25 years ago. And when Goh is told about that truth, he finally understands everything and decides to take drastic action.