Paul Thornton, millionaire CEO of Thornton Precision Instruments, hires down-on-his-luck private detective, Seattle's Kenneth Sheridan, to find his missing son Denny-who failed to show up for work eight days ago. Sheridan follows the trail to the abandoned summer home belonging to the millionaire and finds the decaying body of the son, with a handwritten suicide note attached to it. Believing the case is closed, Sheridan returns to his practice. After several months, the father returns to Sheridan with new evidence the young man did not commit suicide, but was murdered. He promises Sheridan a small fortune if the detective can set the record straight and see that the murderer is properly brought to justice. Sheridan reopens the case, and through a series of exciting and humorously drawn clue-driven events, finds not only is there a murder, but a small child, Grace, was molested. A devotee to the Japanese admonition, "The wise falcon conceals his talons," Sheridan disarms wary opponents by hiding himself behind a veneer of soft-spoken ineptitude. Taking advantage of the circumstances at hand, in the role of Avenging Angel, he resolves the case with murderous efficiency.