On his way to work one day, while waiting for the train, Taichi Kurata cautions a man who tries to push his way into line. That same day, members of the Kurata family fall victim to odd forms of harassment: their flower beds are despoiled, a dying cat is placed in the mailbox, the finish on the car is scarred and its tires flattened, and they even discover that the house has been bugged with a listening device. In an effort to regain their peace, they decide to fight back against the repeated attacks. Eldest son Kenta, who works for a TV station, suggests they install security cameras. Then they make it appear that nobody is home to lure their harasser in, only to have Kenta get stabbed in the chest and the intruder escape.
The police later catch the perpetrator, but instead of the man Taichi confronted on the station platform, he turns out to be a rival of Kenta at work. Disgruntled that an assignment he wanted had gone to Kenta, and having heard of the attacks on the Kurata residence, the rival had decided to engage in some monkey business of his own, starting with the damage to the family's car. Then, following another encounter between Taichi and the original offender at the same station, their fence is defaced with paint, and the police are finally able to track down the culprit and take him into custody.
Meanwhile, Taichi, who is currently on loan to the Nakano Electric Parts Co., suspects wrongdoing by the head of the Sales Department, a close confidant of the president. His suspicions get him on the wrong side of both men, but he nevertheless continues to investigate the matter with his assistant, Setsuko Nishizawa, and they discover a complicated scheme set up to repay heavy debts incurred by the sales head. Taichi renews his warnings to the president, who considers him a nuisance and continues to support his manager, ultimately telling Taichi to return to the bank from which he is on loan. But in the end he realizes that Taichi is right about the crisis the company faces, and offers him an apology.
With an assured touch, the author unfolds a suspenseful tale about threats that lurk nearby in this business novel, family tale, and thriller all rolled into one.