Hiroshi Bando works in the Underwriting Department at the head office of Hakusui Bank in Tokyo, where he handles major corporations and affiliates that are experiencing profitability issues, among them the mega-supermarket chain Ippudo. One day a bombing takes place at an Ippudo store, resulting in customer deaths, and the company's stock price plummets. Then a warning e-mail, sent to Chairman Kozo Kazama before the attack, is discovered. With customers already staying away, the company is reluctant to disclose the message, but Bando is more concerned with compliance and releases the information on his own judgment. The stock price continues to flag, which compels a review of the bank's support for Ippudo. Opinions are sharply divided between Bando, who believes a fundamental reassessment is in order, and Tetsuya Nito, who insists that the massive investment the bank has already made in Ippudo means they must double down in order to prevent a bankruptcy that would cause serious damage to the bank's own stability. Nito attempts to put the blame for the bank's losses following the bombing on Bando's shoulders. Meanwhile, at Ippudo, CFO Yusaku Tomobe continues to harbor doubts about the direction the company is being steered by charismatic founder Kazama and the confidantes through whom he has continued to exercise de facto control even after formally stepping aside to become chairman. The old guard's efforts to return the company to profitability have been going nowhere.
While cooperating with the investigation headed up by Hiromitsu Yaen of the Tokyo Metropolitan Police Department, Bando begins an investigation of his own, which leads him to 21-year-old Ko Inunaki, the son of a retailer driven to bankruptcy and suicide after Ippudo forced its way into the neighborhood. Yaen begins pursing Ko as well, but Ko slips away. Then there is a second bombing, and the stock price tumbles again. It puts Bando in an even more difficult position.
Tomobe attempts to force the resignation of both the chairman and the president who acts as his puppet, hoping it will open the way to a rebuilding, but the effort fails. The turmoil grows even greater following a copycat crime, before the bombing is linked to a margin trading scheme that took advantage of the sharp drop in Ippudo's stock price.
A thrilling financial mystery unfolds as banker, police, and suspect all pursue the true perpetrator of the crime.