Chapter 25 focuses on advancing the two threads that will ultimately lead to the who or what, how and why behind the spread of the contagions of the infectious diseases of plague, tularemia and Rocky Mountain spotted fever. The two threads are (1) the Black Kings and whoever is behind paying for their violent services and (2) ordering the culture probe to identify if any of the victim's pathological microbes are "tagged" with National Biologicals' phage-type identifiers that can confirm a culture's origination with National Biologicals by means of a "fluorescein-labeled DNA probe."

This two-pronged plot development is wrapped in advancing Jack's personal internal conflicts aimed at revealing more of his psychological characteristics. The subplot conflicts developed are (1) Terese versus Laurie and (2) his job security after five years of cynicism and sarcasm. Pertaining to the first, Jack gets dinner invitations from both Laurie and Terese giving Jack a second chance to muse over how after five years of social estrangement, he suddenly finds that two women with opposite personalities are both actively attracted to him. Pertaining to the second, Bingham is one breath away from firing Jack for going to Manhattan General again and turning every official in the city against Jack when he has a change of heart because he recognizes Jack's concern about the inception of the contagions.

The chapter opens with Terese and Colleen holding a meeting with the "creatives" at the ad agency to start plan three for national Health hospital's ad campaign. It will focus on "no waiting." It will be kept strictly secret from "accounting" since that department has sabotaged the creatives' efforts in order to undermine Terese's chances at becoming company president. It is not clear yet how this subplot is critical to the main plot except as a means of introducing auxiliary information about the nature of medical advertising, nosocomial infection regulations, varying levels of hospital administrative efficacy.

After Jack nearly gets fired by Bingham, he goes to his office to find that Gladys has sent over the medical files for the index patient case in each of the contagion outbreaks. While examining these to find any commonalities between them, he is asked to dinner by Laurie, then by Terese. Each mention the danger Jack may be in by returning to his apartment, reminding us of the threat posed by the Black Kings gang on hire by someone.

Jack ends his examination of the files with reaffirmation of the common factors (1) of infections first showing symptoms after they were checked into the hospital and (2) of an existing costly medical condition in each: diabetes, back surgeries, asthma.

Next Jack takes a decisive step that might be instrumental in uncovering the truth behind the contagions (if there is a hidden truth). Jack calls National Biologicals and learns that cultures can be traced back to their originating laboratories, in other words, microbes from the hospital infections patients are traceable back to National Biologicals if that is indeed where they began and came from. It would be critical if such a connection were to be made: it should indicate deliberate acquisition and, moreover, deliberate intent.

    With the advances in DNA technology [Jack] thought it was scientifically possible for National Biologicals to tag their cultures, and ... he thought it a reasonable thing to do. ... Jack reached for the phone number [of national Biologicals]. ... Jack asked for the probe [identifier] to be sent over-night express.